The series concludes with the gangbangers taking out their assault on the 55th Precinct. After some grenade explosions, the precinct is destroyed. Cruz knows that Marcel Hollis is behind the attack, and she takes his life, as well as her own. Carlos proposes to Holly, and they are married. Everyone receives their reassignments, and Sully retires. In the last few moments, Sully narrates a look into the future.

Faith begs Fred to return home, but he refuses for a reason that infuriates his wife; Bosco turns a cold shoulder to Maritza's attempts to offer her condolences; Carlos is spectacularly unsuccessful in his attempts to hit on Grace; on the day of his son's funeral, Donald Mann exacts his revenge with the help of a dirty cop by planting bombs designed to kill the police officers he holds responsible for the death of his son; after Mann's lieutenants force a man to crash a car carrying a live bomb into the funeral home where Mikey's wake is being held, Grace takes charge and goes out of protocol to save Rose's life, and Dr. Fields later swears to have her job for it; Kim's decision not to enter the funeral home while the bomb is still live stems not from cowardice, but from maternal instincts; when Mann discovers that some of his intended targets survived the bombings, he sends machine-gun wielding minions into the hospital to finish off the job.

After a fierce gun battle and some hand-to-hand combat, Mann's gunmen are finally subdued by the members of the 55 in the E.R., but not before Orland is murdered and Bosco is critically injured; after Kim heroically puts herself in the line of fire to save Holly and a little girl, she realizes that her days as a paramedic are over, and that her future lies in being a wife to Jimmy and a mother to their children; Grace and Dr. Fields patch up their differences and come to an understanding about her out-of-protocol field procedures; Maritza uncovers the traitor in their midst, who leads her to Mann; Faith steps over the line to avenge her partner.

Feeling betrayed, Doc angrily confronts his former friend, Jerry Mankowitz, an attorney's investigator who tricked him into confiding vital information about a pending malpractice suit.

Steeper continues his by-the-books command style and goes head-to-head with Kim when Doc doesn't report for duty on time; Sasha can't find her off-duty weapon the morning after Doc's party; Faith returns to duty at the front desk despite Fred's wanting her to remain on disability, and discovers that Bosco has lied to her about Swersky's not allowing them to be partners; a panicky Nardo kidnaps Rose and then Bosco in a futile attempt to prove that he wasn't a rat, and makes a shocking choice when he realizes that his days as a mobster have come to an end; to the horror of the squads, Doc takes extreme measures to prevent Steeper from closing the house, and forces Carlos and Kim to risk their lives to do the right thing; Sully returns a favor by reaching out and saving his friend's life in Doc's hour of greatest need.

Chevchenko has Tatiana's son killed; Fred comes home from the hospital; and Davis gets a job offer.

The police officers sort through the carnage and count their dead in the wake of a shootout between rival gangs. While Faith tries to interrogate Fyodor Chevchenko, a ruthless Russian mob boss, Sully worries about the severely wounded Ty and regrets causing the incident. Tatiana chastises Sully for hassling her injured son. Faith worries about Gusler, her ineffective, frightened rookie partner and a weary Doc gets some unexpected, good news about his medical malpractice suit.

Tensions still run high in the Yokas household; Lester preps Bosco for Mikey's hearing, and then pulls a switch when he cross-examines him on the stand, leading to Mikey's getting RORd; Sully realizes what a toll the job has taken on him by his reaction to the deaths of three people in a robbery at the restaurant where he eats breakfast every day; Faith and Bosco answer a call which leads them to Lester's house, where they find his daughter not breathing; Sully tracks down and arrests the restaurant murderer; after Dr. Hickman tells Faith and Bosco that Lester's wife and daughter have been severely beaten, Lester is arrested; Sully gets his LSAT results; Ty and Sasha get closer.

Maritza calls on her own experience to persuade a rape victim to identify his attacker and sign a complaint after she collars the perp and gets a confession; Ty's prison visit to his father's killer has devastating consequences for both of them; Faith frantically searches for her son when Fred's girlfriend reports that he's missing; the former partners come to blows after Ty accuses Sully of being part of the cover up in the death of Ty's father; both Ty and Sasha deny telling I.A.B. about the knife when Maritza questions them; Sasha uncovers further details about the conspiracy to murder Ty's father and the ensuing cover up.

Although Dade encourages him to keep quiet, Bosco tells Swersky everything that transpired with Maritza, Noble, the death of Willie G, and the shootout in Noble's hotel room, and confesses that he killed Noble after Noble pulled out a gun, Faith was shot by Maritza, and that he grazed Maritza's head with a bullet to keep her from killing Faith; wracked with grief that his wife has a bullet next to her spine, Fred attacks Bosco and threatens to kill him when he discovers that Faith became injured while she was helping her partner out of yet another jam; a critically injured Lt. Johnson, in excruciating pain and with only hours to live, begs Jimmy and Doc to ease his suffering; overwhelmed at the sight of Lt. Johnson's wife lashing out in heartbreak and anger, and her husband's horrific suffering and imminent death, Doc sadly helps out his boss one last time; Swersky has Maritza arrested when she refuses to tell him what happened during the shootout; Bosco learns that Noble was working f

The Boscorelli family suffers a tragic loss at the hands of Donald Mann, who blames Bosco, Faith and Maritza for the death of his son in a high-speed chase; the Yokas family heads off in different directions; the Martin family splits apart into separate jail cells for the parents, and a return home for Rebecca to the mother from whom she was stolen as an infant; the paramedic family at the 55 gets a new member, Grace Foster, which makes no one involved very happy.

When a blackout strikes the city during a heat wave, Sully prophetically warns the more optimistic Ty that trouble in the streets will swiftly ensue. After Carlos leaves the ambulance running to keep the bus cool while he and Doc are on calls, the engine catches fire and the ambulance is destroyed. A wealthy old man confined to his bed by illness offers them a large amount of money to stay with him until his daughter arrives. Doc insists that they leave to treat others more in need over the protests of Carlos. Bosco arrests a young man, Latrell Griffith, and faces a difficult decision when an immigrant shop owner shoots and wounds a teenage shoplifter. After Latrell uses his training as a medic to save the boy, a riot breaks out and Bosco, Latrell and the shoplifter barely escape. Nightfall brings more unrest as the nervous cops try to keep the peace. Faith and Fred are stuck in a elevator when the power goes out. Faith tries to calm Fred's mounting anxiety about being trapped, and is

Bobby's attempt to keep Paulie away from drugs ends tragically.

It is September 21, 2001, and the squads continue to battle through their emotions and their misgivings about their hero status, while working double shifts and spending every free moment at "the pile" searching for the missing. Kim returns to work and teams up with Doc, which allows an emotionally frayed Alex to return to paramedic duty; an exhausted Sully attempts to co-exist with his prospective in-laws while he waits for an opportunity to marry Tatiana.

Bosco, Yokas, Sully and Davis search for a cop killer on the streets, and cope with an obnoxious new sergeant at the station house.

Sully hits bottom when Ty washes his hands of the partnership after Sully's drinking goes completely out of control; a thief strikes fear in the hearts of the police when he phones in false ""officer-in-need-of-assistance"" calls to cover his fur store robberies; Faith and Maritza go at it after Maritza's lonesome cowboy tactics nearly get another cop killed, and Faith is forced to shoot a perp to save Maritza's life after she goes after the perp without backup; Doc has an unpleasant encounter with Joy's father; Faith is disgusted when she finds out about Bosco and Maritza, and Maritza confirms that she put Bosco in front of a lie about a dying declaration to obtain a conviction on a drug dealer; Ty overcompensates for Sully's inattention to the job by becoming a ""supercop"" with an eye to getting a gold shield.

Bosco is dismayed as he watches Cruz go to the extreme lengths of planting drugs, frightening children, and faking a dying declaration in their attempt to arrest the drug dealer who killed another dealer and then tried to to kill the 12 year old boy who witnessed the crime; Nancy tells Ty that she's ending her relationship with Hancock, and gives Ty the ammunition he needs to get out from under Hancock's thumb and back to duty at the 55, as well as getting Sully's suspension from duty lifted.

After she realizes that telling the truth will mean and prison sentence and never seeing her children again, Faith reluctantly agrees to go along with Maritza's cover story that she shot Mann as he was trying to stab Maritza; Yoshi slips out of the cuffs and into the wind; Sasha and Ty hook up; Maritza gets a tough new boss who's been charged with keeping her on a very short leash to curb her renegade ways; Faith goes ballistic when Fred has her served her with divorce papers at the station house; Swersky shuffles the partnerships, and assigns Faith to ride with Sully and Sasha to ride with Ty; Maritza gets an anonymous call that there's an I.A.B. plant in the house who's after her, and she immediately suspects that it's her new boss; Faith decides to turn down the promotion to detective that she's offered for saving Maritza's life until Sully reminds her that the new assignment will improve her chances of getting custody of her children; Bosco's surgeon gives Faith a devastating progn

During the investigation of the gang shootout, the police officers are questioned and presented with evidence that suggests that Ross was killed by friendly fire; Carlos learns that Vangie is dead and that he is the father of the baby her sister leaves at the firehouse; on the first anniversary of Bobby's death, Kim quarrels with Jimmy over her visitation with Joey and confronts a female gang during a call; and Doc is visited by the father of a former patient whose debilitating injury may have been caused by Doc's error during treatment.

Internal Affairs drops the bomb on the envelope-pushing Detective Cruz as she is taken away and struggles to survive in jail, while Captain Finney drills Detective Yokas for information that will nail Cruz - but the torn cop secretly knows that she pulled the trigger on a career criminal that frames the case against Cruz. Officer Sullivan reveals more about his running feud against Finney and his rookie son. Carlos and Levine keep getting called to help a suicidal woman. Bosco's condition changes.

On his last day on the street, Doc's guilt and grief over Alex's death emerges as anger towards everyone he encounters, especially Eugene, the new paramedic trainee whose place Alex took the day she died; Kim becomes frantic as she fears that she have been exposed to HIV after having unprotected sex with a drug addicted Noble, and Jimmy agrees to accompany her when she gets tested; Swersky goes to bat for Faith by creating the opportunity for Bosco to talk to her before she's interrogated by I.A.B.; Carlos is less than thrilled when he discovers that Kim is the new supervising paramedic and Jimmy has been promoted to take over Lt. Johnson's position; Bosco returns to work and faces a hostile reception from the squad for ratting out Maritza; Faith awakes to discover that she's paralyzed; Maritza refuses to let Faith off the hook for shooting her until Bosco tricks her into recanting her story; Faith thanks Bosco for keeping her out of jail and saving her job, and then tells him to get l

Sully and Maggie reconnect; Bobby visits his brother Matty and tries to prepare him for his release from prison; Sunny asks Kim for a place to stay and runs away when Kim refers her to a shelter; Carlos hits a pedestrian with the bus; Faith and Bosco investigate a grave robbery and ponder immortality; Jimmy rescues a new recruit who is trapped under a collapsed ceiling in an apartment fire; Bobby takes Doc's advice and tells Kim how he feels, only to learn that Kim feels she isn't good enough for him; Sunny ODs and Bobby helps a saddened Kim find out her real name and hometown so that her parents can be notified; Sully's approach to ""problem solving"" goes horribly awry in a domestic dispute; Carlos and Doc come to blows over Doc's training methods, forcing Morales to break them up; Sully learns that Ty has good instincts, enabling them to save a teenage girl from a sexual predator.

As Faith waits for Emily to awaken from her coma, she blames everyone but her daughter for the overdose and reflects on the substance abuse problems in her family; after Cruz's sister is brought into the hospital with an overdose, Cruz gets Sully, Ty and Bosco to look the other way on any possession charges and sets off with Bosco to find the location of her supplier's meth lab, where they end up in an inferno when the dealer sets the house on fire; Kim is reluctant to give a statement in Carlos's case because she's feeling pressured to lie to save his career.

Kim and Jimmy are having a custody battle over Joey. Boscoe and Faith are on a call of a possible terrorist threat, that ends up being an explosive event. Alex risks herself to save a little girl and is punished by Doc for it.

After a despondent woman steps off an eight-story apartment building, the squad finds themselves in a race to transport both the woman's heart and a dying girl to a local hospital in time to save the youngster's life. The suicide hits home for Faith as she comes to grips with her own ongoing medical problems, while Doc expresses concern over the emotional effects this case will have on Kim, despite her constant reassurance that her accident was not an attempt to kill herself.

Carlos has a life-changing experience in the hospital after he falls down the fire pole. Tatiana leaves her mother-in-law alone in the house for a moment, with disastrous results.

Faith, Bosco, Sully, Ty and Candyman race through the neighborhood on foot in pursuit of a trio of Uzi-armed thieves; Candyman risks his life to save Ty; Bosco's cold refusal to get medical assistance for one of the perps leads to the robber's death; Ty searches for the truth about his father; Bobby's mother tells the police where to find Matty, who desperately pleads with Bobby to give him some getaway money; Bobby agrees, but begs Matty to turn himself in; Matty gets high and takes off, leaving Bobby crushed and seeking consolation from Kim; and Carlos finds out about Doc and Morales.

Faith negotiates the end of a live on TV hostage situation. The leader of a vampire cult holds Emily hostage until Bosco saves the day. Cruz attempts to negotiate a deal with a gangbanger to end the war on the 55th Precinct, but instead, he organizes his troops to attack.

As she keeps vigil by Emily's bedside, Faith recalls her first days at the Police Academy and the beginning of her friendship with Bosco; the fire squad rescues Bosco, Maritza, and a very pregnant Linda Barnes from the inferno, but Lettie Cruz succumbs to her drug binge before they can reach her; Emily is released from the hospital and takes responsibility for her overdose; Bosco tracks down Gary Barnes with Linda's help; Maritza and Bosco's relationship goes to a new level when he attempts to comfort her on the lost of her sister; Kim finally testifies before the review board and stands up for Carlos.

Emily discovers just what Faith's job entails and how much her mother loves her when they are taken hostage during a bank robbery, and Faith risks her life to save her daughter.

Kim is invited to a party by Noble. Noble is arrested through an undercover operation. He becomes an informant and helps Cruz and Bosco bust a Meth ring. Faith officially requests a new partner. Emily and Faith face off about Eric.

No one can find Bosco after a sexual assault suspect is found dead. While Bosco spends time with family, Yokas, Ty and Sully try to clear him as a murder suspect. Still locked in a custody battle over Joey, Jimmy and Kim meet with a court-appointed evaluator and plead their cases. Alex tries to stay busy to avoid dealing with her feelings about her father's death.

Ty rats out Sasha to the squad after Finney refuses to transfer her out; an action star doing research for his next movie goes on a ride along with the firefighters, and Stu quickly discovers that his boyhood hero is a failing alcoholic looking for a chance to revive a dead career; Brendan offers to ride with Sasha when everyone else refuses to do so, which leaves Ty and Sully partnered again; the retired detective who gave Sasha the real I.A.B. file on the death of Ty's father is found murdered by a police-issued bullet; Sully decides to testify against Finney; in pursuit of a drug dealer who shot an eight year old girl, Sasha and Brendan are injured, but the other units in the sector fail to respond to their calls for help until Ty and Sully finally relent and come to their aid.

The news that Faith is repartnering with Bosco outrages Fred; Bosco overcomes his initial wariness about his brother's claims of sobriety after the tip Mikey gives him about Ecstasy dealers leads to a solid bust; in the wake of the hostage situation, the department shrink sent to debrief the house elicits a range of emotional reactions from Kim, Carlos and Holly as she reveals that Doc is in the Bellevue psych ward on a suicide watch, and that the toll of 9/11 and its aftermath may be at the root of his collapse; when she investigates the murder of an Ecstasy dealer outside a rave, Maritza discovers that the motive may be a turf war between rival dealers; Bosco is distraught when Maritza informs him that the evidence points to Mikey's being a major Ecstasy dealer who used him to eliminate the competition by providing the tip that lead to the raid; Bosco and Maritza set out separately to find Mikey; tragedy occurs when Maritza and Dade pull over Mikey's car outside a rave.

Sully's stopped drinking, but his poor attitude remains; Carlos gives his two week notice; a blizzard blankets the city and the squads are called in early; an understaffed Doc defies orders and puts Carlos back on the street as the squads are kept busy rescuing victims of the storm; Faith's initial wariness about Emily's new boyfriend Eric turns out to be well-founded when he is brought into Mercy after an overdose of Special K, but doesn't remember where he left Emily after she also got high; Faith, Bosco, Sully, Ty, Doc and Carlos go out to search for Emily, and rush her to Mercy after she's found in critical condition; Faith and Fred blame each other for letting Emily go out with Eric.

Sully is upset when he is wrongly accused of falsifying evidence; Bobby helps one of his former teachers dying from cancer; Carlos deludes himself into thinking that Kim is falling in love with him; Sully gets closer to his pretty neighbor.

Ty, Sully, Bosco, and Faith rush to the scene of a school shooting; Sully and Tatiana ponder their future together; Kim continues to struggle with her depression.

Maritza goes all out on the hunt for Michael after Dade dies, as does Bosco, who's intent on finding his brother before Maritza does; Faith calls Maritza a liar in front of Swersky when Maritza claims that she saw Michael shoot Dade; Fred is still angry about Faith repartnering with Bosco, and refuses to discuss it; Breene revisits the house and urges the paramedics to talk to professionals or to each other to help deal with the stress of the shootout; looking to collect the reward for information leading to Dade's killer, Anthony tells Maritza where Michael can be found after she lies to him about her relationship with Bosco; Bosco finds Michael moments before Maritza, and his brother claims that he's innocent and that a drug dealer named Spider was Dade's murderer; Spider comes out with machine guns blazing when Maritza, Sully, Ty, Faith and Bosco attempt to arrest him, and a ferocious gun battle ensues; Maritza agrees to work with Michael as an informant after Bosco pleads for his

In a last-ditch effort to save Sully's life, job, and pension by getting him dried out, Ty and Bosco kidnap him and bring him to a cabin deep in the woods where he hallucinates about the circumstances surrounding the deaths of Tatiana, Chevchenko and Ty's father, and his subsequent descent into alcoholism.

A rapist attacks three victims; Yokas agonizes over her finances, her marriage and her pregnancy; Bosco's jealousy threatens his relationship with Nicole.

Faith rebuffs Bosco's attempt to apologize for lying to her; the fire squad extricates a driver impaled after crashing into a store; after Doc makes an impassioned defense of Carlos before the review board, a re-energized Carlos goes back out on the street; Sully's job performance continues to decline as he neglects to keep an eye on a woman he was supposed to be guarding, and she snatches her critically ill baby from Mercy's E.R.; after they discover that the woman is mentally ill, Ty takes a multi-story tumble while trying to prevent her from jumping off a roof with the baby; Faith is stunned when an initially reluctant Emily is eager to continue visiting a drug counselor; Ty catches Sully drinking in the R.M.P. and seeks advice from a union rep; Carlos loses his job as part of the department's settlement with the West family.

Jimmy gets a promotion to a rescue squad in Brooklyn; despite their new captain's assurances, Doc suspects that he intends to close down the house; Sasha insists upon pursuing an investigation into the beating death of a hit-and-run driver after Maritza uses the confession of an innocent man as her stepping stone to an Anti-Crime reassignment; after Jimmy is trapped in a warehouse fire, Kim reassesses their plans for a future together; Rose's serves a customer at the bar who shares a past with Bosco.

Faith and Bosco hunt down the dealer who distributed a batch of lethal heroin; depressed over Bobby's death, Kim attempts suicide.

The three squads are stationed at the Waldorf-Astoria Hotel to provide protection during a Clinton-Giuliani Senate race debate. The cops are assigned to the kitchen and discuss politics and the death penalty while Sully tries to get a reluctant head chef to feed them. The paramedics are parked in the hotel's garage where they talk about their worst cases, religion, relationships, and how life doesn't turn out as planned. Kim and Jimmy have it out again over his irresponsibility after her paycheck is garnished to cover one of his bad debts, and Jimmy resolves to clean up his act.

Finney continues to press an increasingly reluctant Sasha for information on Faith; Carlos gets nowhere trying to put the moves on Grace; Ty gets promoted to a Field Training Officer and is forced to contend with Brendan, an impulsive and hot headed new police officer who also happens to be Finney's son; after Faith is unsuccessful in getting any of her family members to attend her promotion ceremony, a wired Sasha takes her out for a drink afterward and tries to engage her in conversation about Mann's death; after complaining of boredom, Brendan is forced to watch in horror as a woman is broadsided by two different cars in a terrible car accident; Carlos is spooked after he suffers a series of minor mishaps in the wake of an irate fortune teller's putting a curse on him, and Grace has a little fun with him when she takes full advantage of the situation; Sully tells everyone who'll listen that Finney is a corrupt cop, and that his son doesn't belong in their squad; Holly does a ritual

A secret threatens to destroy Jimmy's relationships at work and home; Sully makes a date with his pretty neighbor; Bosco gets violent after his mother is beaten by her boyfriend.

The two rookies, Carlos and Davis, experience disillusionment with their new jobs, and their training officers. Bosco struggles with Homophobia and gets himself involved in tit for tat games with Doherty.

Yokas continues to have marital difficulties with Fred and, when she meets up with an old flame at the scene of a car accident, she finds herself very tempted to accept his invitation to meet him in his hotel room to catch up on old times. Doc's dad ends up in intensive care leaving Doc with some hard decisions. A perp accuses 'Candyman' of stealing money from him when he arrested him. Davis believes the criminal and is not sure how he is going to answer IAB's questions about what happened, even though he didn't see anything happen. The police station takes on the fire station in a basketball game.

Bosco gets a temporary assignment working with a tough female sergeant; Fred is strangely calm in the face of the prospect of a triple bypass; Doc hears shocking news from Philadelphia; Sully learns more about Tatiana's past; Davis is forced to deal with his newfound fame.

Dealing with the aftermath of gang warfare, Doc and Carlos disagree over reaching out to prevent an eleven year old boy from following his brother into a gang; Bosco's decision to turn the tables on two men who try to rob him when he's off-duty could cost him his badge when the two men turn up at the precinct to report the crime; as he continues his losing streak, Jimmy gets deeper and deeper into his bookie, which puts Joey in danger; Kim begins to worry about how much time she spends with Joey after he gets into trouble at school.

It's Valentine's Day and Bobby and Kim have spent the night together; Bobby's confession of love leads Kim to realize that they've made a big mistake; after agonizing all day, she finally confesses and breaks Bobby's heart; seeking solace in a bottle, Bobby finds himself at a local bar next to a woman who has also been jilted that day, and they go off to her place; Fred drunkenly totals the car on the way to pick up Emily and Charlie; Faith arrests him and refuses to bail him out; when he finally arrives home, Faith has his things already packed and throws him out; Carlos tends to a girl who runs into a bus and then falls for him; the gay community is targeted by a gunman and a vigilante group forms to find the killer; Ty arrests a girl for auto theft who turns out to be Malcolm's sister; and Faith lets Bosco know that she is fed up with his bigotry.

Sasha, Bosco, Sully and Ty get on the case of a malicious rapper. Ty considers returning to law school with the help of Sully. Jimmy struggles with his new position and his relationship with his co-workers when he makes a big mistake during a fire drill. Faith gets a physical therapist.

Doc and Carlos attend a stress debriefing; Carlos meets up with Bosco when he's ordered to attend sensitivity training.

While coping with work demands, a recovering alcholic husband and a disturbing visit with her parents, Yokas confronts her long held beliefs and emotions. A group of prisoners escape from a delivery truck. Yokas and Fred have another big fight in which she accuses him of drinking again. She tells him that she had an abortion. He wants her to leave the house, this makes her stay over at her parents home. However, by the end of the episode, they are back together, she realises that she can't live without him and that she is sorry for accusing him of still drinking. Meanwhile, Bosco gets a bunch of flowers from a former lover. He smells the flowers which turn out to be poison Ivy. Bosco and Yokas also have a fight when she tells him that she had an abortion. He accuses her of lying to him and he refuses to speak to her, until she forces him to go the hospital to sort out the poison Ivy problem. She regrets lying to him.

Faith's excitement over having her husband to herself for the weekend is dashed when Fred decides to spend the time trying to win a truck; angry, Faith organizes a drunken girls night out, meets a handsome photographer, and ponders an affair and what might have been; Fred outwits his opponents and wins the truck.

Doherty shows his bravery trying to save the mother of two young children from a fire. Meanwhile Bosco and Faith are out looking for the man suspected of starting the fire in the first place. Davis tries to set Sully up on a blind date and after her pimp beats up Malcolm's sister they try to find him before he kills the man who did it. Carlos' girlfriend problems escalate and Doc's relationship looks like going to the next stage.

Doc, Carlos, and Ty each feel guilty about the mistakes they made during Jerry's shooting; Jimmy gives Kim a bulletproof vest; the squads rescue a man dangling from the side of a skyscraper after an explosion; Fred wants Faith to quit her job; initially reluctant to discuss the circumstances surrounding Ty's father's death when Ty asks, Sully finally relents; Carlos and Ty commiserate about their partners; Sully's contacts on the street pinpoint an abandoned building as the location of Jerry's shooter, and Bosco takes the shooter down -- out a second floor window.

Ty is worried about Sully's dating Maggie; Faith and Bosco lose a witness who turns out to be the perp in a homicide; Bobby prepares for Matty's release from prison; while driving the bus, Carlos collides with a pregnant driver and later attempts to revive the baby she delivered prematurely after Sarah pronounces it dead, unaware of the consequences for the parents; Jimmy rescues a boy from a tree; Bosco and Ty take issue with Sully over his handling of a belligerent collar.

Mercy's new E.R. attending gives the cops and paramedics a hard time while ignoring Carlos's attempts to hit on her; Doc is saddened to hear that Jerry has decided to take a disability retirement; Jimmy is upset when Joey goes to Bobby first after he becomes ill as a result of Jimmy's letting him overindulge in sweets; Jimmy and Bobby take out their conflict over Kim and Joey in a game of one-on-one; Sully and Ty arrest a purse snatcher who will do anything to stay in jail once he discovers that his victim's son is a mobster; Faith hands out street justice to a gangbanger responsible for the deaths of two little boys.

Bosco is caught on a security camera having sex in his squad car with the daughter of his Precinct Captain. Meanwhile Doc drags Carlos around the city on a personal mission to find the owner of a watch, found in the ambulance.

Doc is thrilled when Sarah accepts his proposal, but is stunned when she informs him that she's accepting a job offer in Philadelphia and wants him to relocate.

Joey starts a fire while on a field trip with his class, causing Kim and Jimmy to reevaluate their parenting styles and inspiring Kim to try to rebuild her family, starting with a reconciliation with Jimmy. But Jimmy's relationship with Brooke is not nearly as wobbly as Kim would like to think, and Kim ends up jumping into bed with a stranger and then commiserating with her mother over her problems with men, ending in a confrontation with Brooke that forces Kim to rethink what's best for Joey in the matter.

Yokas and Bosco chase a carjacker into a multi-level garage. When the thief drives off the edge of the top level and crashes to the ground, Bobby risks his own life to save the driver. Much to the surprise of everyone who knows him, Bosco goes to the opera with Nicole and her parents. Carlos gets into trouble with his boss and Vangie. Sully and Ty go to help Candyman on a job, and Ty tells Candyman exactly what he thinks of him. Jimmy has news for Kim which surprises her, and annoys Bobby everytime Kim tries to talk to him about it.

Faith, Bosco, Carlos and a wounded Doc find themselves trapped in an abandoned tunnel and unable to reach Central on their radios; the firefighters get into mischief during a long lull between calls; when the C.O. can't raise Bosco on the radio, Sully tries to cover for him.

Steeper exiles the paramedics to permanent fixed posts on the street, which upsets everyone on the squad except Doc, who refuses to let anything put a damper on his unusually upbeat attitude; Carlos is less than thrilled when Doc invites Christian to accompany them on a ride-along without getting the proper authorization; when Bosco goes after Nardo for his veiled threats against Rose, Nardo tries to set Bosco up to look like a dirty cop; Rose is fired after Bosco destroys poker machines owned by Nardo in the bar where she works; on the eve of her return to duty, Faith tells Bosco that she wants to repartner with him; Sasha's second thoughts about the plan she and Bosco hatched to repay Nardo for threatening Rose and attempting to frame Bosco turn out to be on target when Nardo flees after murdering two men; Doc and Sasha hook up after Doc throws a big party at his house for his co-workers.

Sully kills one of the perps and shoots the denotator out of the hand of Frank Morgan, the bomber; Doc goes ballistic when he comes upon the scene of an accident involving his old rig and a city bus, and physically assaults Eugene; Public Morals raids Dr. Chow's office, and Maritza is forced to reveal her rape to keep Thomas Warner from being released on a D.A.T.; Ty gets Frank Morgan to flip on Gary Barnes, and Barbara promises Morgan that she will make sure he gets the death penalty for killing her housekeeper and driver; Kim and Carlos refuse to back up Eugene after he files a complaint against Doc, prompting Eugene to quit; a distraught Faith, still plagued by flashbacks of the shooting, asks Fred if they can get out of the city for a family vacation; Warner confesses to raping Maritza while Bosco is transporting him to the Tombs; Carlos is horrified when Doc admits that he accosted Eugene at his house because he ""killed Taylor""; Bosco turns Warner over to Maritza, who gets her pay

A disturbing visit from his former high school girlfriend forces Doc to confront a horrible act he has hidden for years; Carlos struggles to pass a medical school qualification exam.

Davis rescues a drowning newscaster from a downed helicopter, and the ensuing rush of media coverage on his heroism brings a strange young woman to meet him. She turns out to be his half-sister, and Davis uncovers secrets about his father's second family. The turmoil from the revelations causes disturbances between Davis and nearly everyone close to him. Meanwhile, someone's throwing bricks at random citizens, putting everyone in the city on edge.

Barbara is heartbroken when she discovers that her housekeeper was killed by the explosion; Sasha convinces Maritza to get a rape exam; Sully takes Barbara to his house to keep her safe; Maritza discovers that her rapist, Thomas Warner, has a history of sexually assaulting the workers at the clinic; undeterred by yet another attack on her life, this time by a sniper, Barbara insists on presiding at the preliminary hearing of Gary Barnes, the drug dealer who the police suspect is behind the attempts on her life; Faith visits a psychiatrist and unloads her anger at Bosco and Maritza; after Maritza testifies at the hearing, Barbara rules that Barnes can be held over for trial for the death of Lettie Cruz; when Sully sees Barnes signal a spectator in the court room, he and Ty follow him to a house where they see him join the man who delivered the bomb to Barbara's house; the perps, armed with a detonator, threaten to blow up the block with the explosives they claim are in the house and for

Everyone in the 55th Precinct faces their worst fears when terrorists are discovered to possibly be building a dirty bomb. Carlos and Levine face trouble in their relationship. Captain Finney decides to end his life, rather than surrender himself for the murder of Ty Davis Sr. Brendan and Davis try to cover it up.

Bobby comes to the aid of his old friend Paulie after Paulie's sister begs Bobby to help her brother with his drug addiction, but becomes enraged when Paulie breaks into Bobby's mother's house and robs her to support his habit.

On Thanksgiving Day, Bosco tries to resolve a family conflict in a restaurant while Faith deals with the same thing in her own home. Bobby's mother refuses to allow Matty to attend the family's holiday celebrations, and leaves it up to Bobby to tell his brother. After a shooting, Ty and Sully disagree over how they should report the incident to their superiors and the investigating team.

Finney gets a frantic phone call from Ben, a child he had helped in a previous case, which said that Ben's father was hurting Ben's mother and coming after Ben. Ben's father takes him to an abandoned warehouse, where the police soon follow.

Doc supervises a new paramedic on her first day; Carlos is arrested after a teenaged patient accuses him of molesting her; Bosco and Faith search for an escaped prisoner; Sully and Davis team up with fire and EMS to save construction workers when their scaffold collapses; in the aftermath of the bank robbery, Faith is troubled when Emily asks her how many people she's killed in the line of duty.

Tatiana is still missing, and Sully continues to search for her while grieving her loss. When he comes upon the body of a six-year-old girl in a box on a curb, he becomes strangely unnerved. Haunted by this sight and by thoughts of the mistakes he has made recently, Sully takes the rest of the day off sick and winds up in a local restaurant where he finds his parish priest. They ruminate on the nature of guilt, absolution, forgiveness, faith, and the intercession of God as they recall the fate of another man who also made mistakes and tried to fix them, and whose life ended tragically at Sully's hand. Sully finally comes to a place where he can forgive himself and go on with life. He seeks out Davis to once again beg his forgiveness and reaffirm their connection to each other.

Ty bails Carlos out and unsuccessfully tries to help him smooth things over with Nicole; after Bosco and Faith break up a domestic disturbance between an old friend of Faith's and her lover, Faith convinces her friend to leave the abusive relationship; Alex gets irritated when the other firefighters make fun of her brother; Sully continues to drink and have a poor attitude on the job; Jimmy is appalled when his face appears on a poster for an erectile dysfunction product, and is stunned when he discovers that the company paid the charity for whom he posed for the picture $10,000 for the right to use the picture, and that their website got 3,000 hits the first day from women wanting to know his name; when he discovers that everyone thinks that he's guilty and he's likely to lose his case, Carlos resigns in the hope that Nicole will drop the matter, and he'll be able to avoid a conviction that will end his visits with Kylie and his hopes of becoming a doctor.

As he comes around a corner in pursuit of a gunman, Davis shoots a man who is pointing a gun at Sully, unaware that the man is innocently returning the service revolver which Sully dropped when he fell. Davis's guilt leads him to doubt whether he should remain on the force, until Sully straightens him out. The tension between Bosco and Faith continues to escalate. Both Bobby and Jimmy introduce their new girlfriends to Kim, who isn't thrilled with the potential competition.

Doc is up for paramedic of the year and is being followed by a film crew. Doc may have made a medical mistake when treating a patient. Faith recovering from cancer treatment and on the job fails to back up Boscoe while chasing a suspect.