Uncle Teddy appears surprisingly stoic after a staggering personal loss, but finally bursts at the seams and has the gang cornered. Janet and Sheila's plan goes haywire and leaves a trail of destruction in its wake.

Franco steps into the ring with one of Carla's friends;Tommy tends bar after a failed rescue leaves the crew in the dumps.

Tommy's sister suddenly shows up in town when their dad is about to inherit a million dollars. Tommy and Janet decide to renew their wedding vows. Meanwhile, Mike is worried when he finds a lump.

In the aftermath of the fire, the members of 62 truck struggle to pick up the pieces and look towards the future. Down at The Rock, the new probies receive a familiar speech and stand before a new leader.

After a game of street hockey, Sean takes some sleeping pills believing they are painkillers and it has an unwanted consequence. In the meantime, Tommy and Angie decide to go on their fake date that they know will upset Janet. After having a close call, Lou gets a new angle on firefighting from his Uncle Red.

Tommy copes with a tragedy. Jerry must decide what to do when his wife's condition worsens. Sean has a crisis of faith. Lou learns some shocking facts about Candy. And the crew responds to a multi-level building fire with people trapped inside.

When Tommy, Johnny, and Mickey confront Father Murphy it results in tragedy. Sheila needs Tommy's help with a domestic issue. Jerry decides it's time to get a nurse to care for Jeanie. Lou offers to help Candy out with her situation. And Laura discovers the truth behind Franco's poetry.

Tommy starts taking Janet's antidepressants. When Sean meddles in Franco and Laura's troubled relationship he makes things worse. After a gay visitor, the crew wonders about Mike's sexuality.

Tommy and Janet attempt to survive a weekend together at Katy's new prep school. Meanwhile, Lou sees Tommy's absence as a way to move in on Genevieve. Teddy and Maggie receive vulgar propositions and Sean's stomach pain acts up at an inopportune moment.

In the tradition of the Gavin family, Colleen's wedding is an emotional if not debaucherous affair. The high spirits quickly fade, however, when the guys tackle the mother of all fires.

Franco has his first FDNY-tournament fight, and he and Carla (Tawny Cypress) have an encounter outside the gym; Candy cooks dinner for Lou; the guys have a surprise for Sean when they visit him in the hospital, and he has one for them. The guys also plan an outing for the kids in the cancer ward.

What starts as a controlled interview takes a turn for the worse, ending in a full-on brawl. The beef continues even after the guys survive a harrowing scenario at a call.

The hockey game rematch between the NYPD and the FDNY is right around the corner and Tommy must figure out a plan to save himself from being pummeled by the cops who have it out for him. Tommy's relationship with Sheila is discovered by the guys and they must adhere to tradition to handle it in their own way. When Tommy is visited by his demons during a fire, Franco comes to his aid... with devastating results.

The perfect party becomes a nightmare when a herd of brutish women infiltrate the bar. Tommy's love triangle reaches new heights.

The Gavin family AA group's first meeting doesn't go exactly as planned. Tommy bribes Colleen for information on Janet. Franco learns the truth about Natalie from Richie while Lou contemplates revenge on Cousin Mike.

Tommy ends up promising Janet that he will help her with the baby, but neglects to tell her about his future plans with Sheila. Meanwhile, Franco decides to check up on his daughter, Keela.

Tommy seeks the truth about Sheila while trying to get his kids back; Lou does not like the person he has saved through a bone marrow donation; Franco's addiction puts those he loves at risk; Sean's new girlfriend habitually dates firemen.

In the fourth-season finale, Sheila learns that Jimmy's ghost has been spotted on several occasions, so she investigates. Meanwhile, Colleen blames Tommy for her failed relationship; Franco and Natalie come to an understanding, as do Lou, Cousin Mike and Latrina; and Tommy spends time with his father.

When Tommy struggles to help Janet in a financial crunch, he must turn to his Uncle Teddy to help him out. The new female addition to the house fights to be accepted by the guys while they do everything they can to drive her nuts. Just as Mike is getting fed up from sleeping on the firehouse couch, he is offered a helping hand with a free place to stay... at a steep price.

An outburst lands Tommy cleaning duty as a mysterious woman strolls through the firehouse; the Gavins confront Tommy about his alcoholism, but their plan does not unfold as expected.

Tommy's fate in the firehouse depends on vote by the crew. Tommy reunites with his dad. Franco and Laura's relationship grows.

Though Tommy's pacts with Sheila and Janet have begun to unravel, there is one Gavin who remains sexually adventurous much to Tommy's chagrin. Garrity divulges his medical secret, Tommy proclaims he's been drinking at AA, but its Mickey who will offer the final surprise.

Jerry forces the crew to attend a birthday party that his son is throwing for his boyfriend. Meanwhile, Tommy makes a move on Mariel after she tells him she might not be his half sister after all. Franco asks Laura to move in with him while Sheila tries to make Tommy jealous by showing off her new girlfriend.

After a run in with Janet's brash new boyfriend, Tommy grows concerned about Katie's whereabouts. Sheila is finally able to come to terms with Jimmy's death as Damien makes the decision to follow in his father's footsteps.

Lou turns to new-age techniques in his efforts to change his life. Sean and Maggie come to a surprising decision. Tommy and Angie continue to see each other, which quickly leads to an embarrassing scene with Janet.

During a night out, Franco and Tommy meet two women. Tommy is finding himself bribing his daughter Colleen before she tells their mother about his indulgent treatment of her sister Katy. Jerry visits his wife Jeannie in her expensive nursing home and soon goes to Lou for financial help. Meanwhile John Sr. insists on having his 83rd birthday at a restaurant that no one else likes.

In an effort to get more time off to search for his wife and kids, Tommy joins the new firehouse’s Barbershop Quartet. Meanwhile back at the old station, Lou and Chief Reilly conspire to get Tommy back, but the rest of the crew has grown fond of his replacement.

Tommy and Janet are brought together once again by another Gavin family tragedy. Jerry ends up not showing up for work. Mike decides it is time to look for some advice about his sexuality. Meanwhile, Maggie has a surprise for Sean.

When a retired gay firefighter makes a published claim that several firemen who died in 9/11 were closeted gays, Chief Reilly is determined to set the record straight. While attempting to mask the pain of losing his wife and kids, Tommy does Jimmy a favor and spies on his widow which leads to a surprising discovery. The probie must deal with the unexpected repercussions of being a hero after making his first save in a fire.

Tommy decides to make life a living hell for his wife's new boyfriend by wreaking havoc on his business and finances. Meanwhile, Chief Reilly faces possible suspension as the result of an altercation with a fellow firefighter and Lou decides to share his poetry.

When Tommy asks for extra vacation time, Chief Reilly tips him off on how to get a free two week vacation from headquarters. While building a deck for Tommy's neighbor, Tommy takes advantage of his "free" advice which leads him to make a bold move in reconciling with Janet.

The Gavin clan stages an intervention after several disturbing family calls; the mysterious woman (Gina Gershon) from the restaurant leaves Tommy wanting more; Janet must take matters into her own hands to get her baby back; and a depressed Mike calls Tommy in a moment of despair

A "friendly" date between Tommy and the widow of his dead cousin takes a unexpected turn when she makes a move on Tommy. Franco's ex-girlfriend shows up at the firehouse and claims he's the father of her five-year-old daughter, turning his life upside down.

Tommy loses his nerve when a young driver's recklessness reminds him of his daughter's new lifestyle. After a meeting fails to put Colleen on the wagon, Tommy is forced to pursue a more aggressive method to get her life back on track.

A day at ground zero inspires Tommy to write letters to his loved ones. When Lou betrays his trust, Tommy returns to ground zero with an old friend.

With Damian confined to a chair and a new baby on the way, Sheila and Janet join forces and shake-up Tommy’s family life.

Tommy attempts to handle the insanity of his father while defending Colleen's new lifestyle to Janet. At the firehouse, Sean and Mike the Probie unknowingly launch a full blown wager among the crew.

Tommy takes one step forward by convincing Janet to leave Roger but two steps backward when she stumbles onto his latest fling. The boys convince Sean to date a woman but neglect to tell him that she is actually a he. Franco discovers he can't shake his newfound fatherly instincts.

When headquarters shuts down the house, the crew formulates a makeshift response to a nearby call. A face from the past stirs Tommy and Janet's emotions as their date begins to unravel.

Janet plots revenge when she learns what Tommy did with the baby; Franco questions his marriage proposal to Natalie in light of Alicia and Keela's return; and Tommy faces his ghosts.

Tension runs high as Needles holds the guys accountable for their lack of judgment. Tommy steps up and takes responsibility for Damian's future in the firehouse. Sheila provides Tommy with an oasis as a sign of her gratitude but it may not be enough to save him from the wrath of Mike, Dwight, and the ghosts of Tommy's past.

With the cookout quickly approaching, the guys hatch a plan to sneak Lou out of the hospital. Sean and Mike attempt to do good, Teddy bonds with Colleen, and Father Phil gives Tommy a piece of advice that sends him reeling.

A devastating fire has a profound effect on the crew; Tommy wrestles with his feelings about the baby; Alicia (Susan Sarandon) returns with a proposition for Franco; Troy breaks up with Sheila while Lou makes a tough decision about Theresa; and Sean apologizes to Mike about the fire he set that burned down Mike's mother's house.

A night of heavy drinking turns ugly when Tommy blacks out and loses control. The next day, the crew struggles to put the pieces together as they search for the whereabouts of Colleen.

Franco demands a sense of responsibility around the house, but a precarious call puts his leadership skills to the test. Lou delivers Tommy's letters unbeknownst to Tommy.

As Damien joins 62 Truck, Sheila reminds Tommy of his promise to watch out for him. Meanwhile, Janet gives Tommy guidelines for their relationship; the guys attend a memorial dedication for a firefighter who died on 9/11; and Sean is released from the hospital, vowing to live life "to the fullest."

The calls from Tommy's AA sponsee increase as Tommy attempts to navigate a touchy issue with Colleen. Genvieve's interviews spark controversial viewpoints in the firehouse concerning the political and religious implications of 9/11-viewpoints which Mike will not tolerate.

Needles' political leverage catches HQ off guard, leaving them no choice but to reopen the house. Feinberg loses control, Damian saves a helpless victim, and Tommy and Sheila find themselves in hot water.

Franco's addiction to painkillers has driven him to a support group to get help with his problem. A young boy clings to life after Tommy saves him from a fire. Jerry is introduced to his gay son's life partner.

Sheila lies to Tommy when he confronts her about the beach-house fire. But they present a united front to the insurance investigators, as embarrassing as it is for Tommy. Meanwhile, Lou is determined to get a basketball ringer (Larenz Tate) to be 62 Truck's new probie; Uncle Teddy is released from jail; Colleen runs away with her rock-musician boyfriend; and Mike's mother has a deathbed request.

A no-nonsense woman, looking for a date, shows up at the firehouse talking trash; Janet offers Tommy an ultimatum; Needles and Lou concoct a battle of the sexes; Sean's medical condition moves lower on his body.

Tommy lays off the antidepressants when he is kicked off the hockey team. Sheila asks Tommy to talk Damien out of being a firefighter. Meanwhile, when Franco sees Laura with another guy he gets jealous and Tommy's dad gets a surprise when he returns home from a three day trip to Atlantic City.

Janet has given birth to a baby boy---whom she fears prefers Tommy to her. But Tommy has a bigger problem: He's suspected of starting the beach-house fire. Meanwhile, Jerry's son asks him to be his best man at his commitment ceremony; Richie wants Franco to marry Natalie; Lou and Theresa get distracted in church; and the volunteer firefighter who rescued Tommy from the beach house takes an interest in him---and isn't shy about letting him know.

Tommy asks his cousin for help in understanding the bizarre visions he's been having. The crew tries to help Laura understand the essence of male comaraderie.

After dealing with a particularly horrific accident on the job, Tommy questions his feelings in a dream sequence with his dead father, brother and son, and Jimmy Keefe. Meanwhile, Sean has an unwanted visitor at the hospital; and Lou has a very-much-wanted visitor to his apartment.

While Tommy and Johnny have another encounter, Janet and Angie re-establish their acquaintance. Meanwhile, Sheila is unhappy when she sees Tommy and Angie together. Maggie wants to get back together with Sean. Mike hooks up with a woman at a bar, making his roommate, Chris, jealous. Franco finds out about Jerry's second job at the pub, and the money in the no-smoking jar goes missing.