Not wanting to continue cleaning up the estate, Mark hires Millie Denton, his former prison cellmate's widow, as a maid. Meanwhile, Hardcastle begins looking into the suspicious death of a lawyer named Charlie Clarkson. Taking over Charlie's practice, Hardcastle interviews Loni Summers, a model that had previously hired Charlie to handle her divorce. Discovering the divorce is now off, Hardcastle checks into the background of actor Dex Falcon, Loni's husband. Investigating, the judge discovers that Falcon had secretly been receiving millions of dollars from an attorney named Wendell Price. In the meantime, Millie, who claims to be a psychic, has a vision of Mark's murder. Ignoring Millie's warning, Mark proceeds with the case. To Mark's regret, he is captured by Price, shot and left for dead. Thanks to Millie, Hardcastle locates Mark in time to save his life. Next, based on the evidence Mark had gathered, Hardcastle and the police, having already taken Falcon into custody, movie in and arrest Price. As the episode ends, Millie, shaken up by her visions, decides to quit and move in with her sister.

Mark is thrilled when he wins $20,000 racing in the Arizona Modified. His joy quickly dissipates when thieves hold him up and steal his winnings as well as the Coyote. Based on Hardcastle and McCormick's description of the thieves, Deputy Sheriff Dan Johnson realizes that they were robbed by locals Arvin Lee and Melissa Kantwell. Complicating matters is the fact that Melissa is the wife of Billy Blackstone, the city's sheriff. After recovering the Coyote from a used car salesman, Hardcastle and McCormick begin to track the crooks. To their surprise, they catch up with Arvin Lee only to discover that he has been murdered. Putting the pieces together, they realize that Blackstone probably killed Arvin Lee. Taking their theory one step further, Hardcastle and McCormick speculate that Melissa only pretended to fall in love with Arvin Lee in order to trick him into stealing for her. With Johnson's help, the judge and Mark locate Blackstone and Melissa. With Blackstone unwilling to surrender, the deputies are forced to shoot and kill him. To Mark's regret, the shoot-out starts a fire that destroys his racing winnings.

In the third season opener, Hardcastle and McCormick go on a photo exhibition with Buzz Bird, one of the judge's old friends. To their regret, Buzz, who is a pilot, has a heart attack while flying them over a stretch of Oregon wilderness. While Hardcastle and McCormick survive the crash landing, they are stranded miles from civilization and unknowingly attract the attention of Taylor Walsh, a mountain "pirate" who has made his living by robbing tourists. After suffering through a horrible rain storm, Hardcastle decides to tell Mark how much he appreciates their friendship. Although Mark pretends to be asleep, he actually hears everything the judge has to say. The next day, the two men come across the dead body of a murdered man. Realizing that they are being tracked, they decide to speed up their journey by white water rafting. Once the two men are in the water, Taylor and his men attack. Fleeing to land, Hardcastle and McCormick manage to evade the pirates. Turning the tables, the two men capture Taylor and his men. A month later, the judge and Mark, with their prisoners in tow, finally return to civilization.

Mark surprises the judge when he not only qualifies for, but becomes a winner on, The 1 Million Dollar Trivia Master, a television game show. Unbeknownst to Mark, veteran game show producers Harry Baxter and Art Healy, envisioning big ratings, decide to help the ex-race car driver along once they discover that the audience is cheering for him to succeed. To guarantee a winning streak, the producers have Hardcastle's estate bugged and begin basing their questions on Mark's home practice sessions. Although Hardcastle quickly realizes that something is amiss, Mark is unwilling to accept that the game is rigged. After Diane Templeton, one of the trivia show's employees, dies under mysterious circumstances, Mark turns around and admits that something is seriously wrong. Searching the show's offices, Hardcastle finds out why Diane was killed: She had obtained a tape proving the show is fixed. Meanwhile, Baxter and Healy discover that Bryce Benson, the shows host, had taken their plan to a deadly conclusion by killing Diane. Not wanting to face murder charges, the producers decide to tell Hardcastle everything. During the taping of the show's final round, Mark, giving up his chance to be a big winner, reluctantly helps the police stop Benson. Hinting at the series eventual conclusion, Mark jokes about going to law school in this episode.

After seeing reputed mobster Stevie Ray kill a man named Tommy Chen, former prostitute Angie Bloom goes into hiding. Before disappearing, she decides to leave Nicky and Lindsey, her young children, with Hardcastle for safekeeping. While the kids initially refuse to tell the judge their name, the judge eventually realizes that they are Angie's children. Meanwhile, Hardcastle and McCormick discover something is amiss when some men unsuccessfully try to kidnap the kids. Following a hunch, Hardcastle pays a visit on a former madam named Dolores. The hunch pays off and the judge locates Angie. Convinced that Hardcastle has her best interests in mind, Angie tells the judge the whole story. Recognizing that the best way to protect Angie is to put Stevie in prison, Hardcastle arranges for her to testify. To his regret, the officers that pick up Angie are actually Stevie's men. Upon learning the truth, Hardcastle and McCormick "convince" one of Stevie's men to tell them where to find Angie. Following up on their lead, the two men capture Stevie and rescue Angie.

Entering the hospital for a routine checkup, Hardcastle discovers that he is dying from an incurable disease. Not wanting to let his friend just fade away, Mark convinces Hardcastle to live his remaining days to the fullest, Taking Mark's advice to heart, the judge, using the money he inherited from his wife, buys a one million dollar boat. Hardcastle's boating career is short lived, however, for armed men steal the boat. Although Hardcastle is initially willing to let the police handle the crime, he changes his mind after discovering that the hospital made a mistake and he is not really dying. Searching the docks, Hardcastle and McCormick locate the boat. Instead of reclaiming his property, Hardcastle discovers that the boat really belongs to an influential Senator. Realizing that Barry Jackson, the man who illegally "sold" him the boat, is a con artist, Hardcastle contacts his bank to find out where his money is being transferred. With Lieutenant Harper's help, Hardcastle and McCormick stake out the bank and capture Jackson. In the process, Hardcastle recovers his money.

When Bill Bauer is declared dead after being MIA from the Marines for 10 years, Mark, the soldier's former best friend, is asked to handle the funeral arrangements. The funeral does have one positive result for it reunites Mark with old friends Patrick Burke, Jeff Steffan and Peter Trigg. To Mark's surprise, shortly after the funeral, Bauer turns up very much alive. Upon being confronted by his angered friend, Bauer explains that he had been in charge of destroying cash when the United States pulled out of Vietnam in 1975. Instead of following orders, however, he had waited for an opportunity to smuggle the money into the country. Continuing, Bauer relays how he used "his" casket as a way of transporting the cash. Bauer realizes that his plan is falling apart when someone tries to kill him. Seeing no alternative, Bauer decides to go after the men chasing him. Following Bauer, Hardcastle and McCormick discover that Peter Trigg, secretly the leader of a group of terrorists, is trying to get a hold of Bauer's money in order to buy weapons. Although Trigg temporarily manages to capture Hardcastle and McCormick, the two men are able to turn the tables thanks to Bauer's intervention. Later, the police are all set to take Bauer into custody when the ex-soldier decides to disappear again.

As the final episode begins, Mark, who has secretly begun attending law school, is offered a paralegal job by Kenneth Malcolm, one of his professors. Meanwhile, Hardcastle, realizing that Mark's parole is up, decides to buy a car repair business, as a surprise gift for his friend. Upon hearing about Mark's job offer, Hardcastle, not wanting to stand in his friend's way, lies and tells his friend that he bought the company for himself. For his first assignment at law firm Malcolm, Hughes and Dewitt, Mark is asked to reclaim the possessions of Elsey, a resident of the Sunset Acres Retirement Home. Arriving at the home, Mark makes the acquaintance of Mimi LeGrand, a retired actress. Immediately liking Mimi, Mark is more than willing to comply when the former actress asks him to open a bank account for her. To Mark's surprise, he discovers that someone has already opened an account in Mimi's name. Concerned, Mark decides to go to Hardcastle for help. Before the two men are able to really learn anything in the case, they end up in jail as a result of a mistake made by Leroy, Hardcastle's assistant at the car company. While awaiting their release, Hardcastle decides to tell his friend the truth about why he bought the company. In response, Mark reveals that he has been going to law school in an attempt to follow in his friend's footsteps. Once released, Hardcastle and McCormick discover evidence that Malcolm and resident home manager Leonard Porter have been killing the residents and stealing their money. (They were able to move the money by secretly creating bank accounts in the seniors' names.) Armed with sufficient evidence, the crime fighting duo stop Malcolm and Porter. Despite the fall of his professor, Mark vows to continue attending law school. After selling the car business, Hardcastle makes a generous bet with Mark: If the ex-race car driver can beat him in a game of basketball, the judge will pay the law school bill. Due in the most part to Hardcastle's generosity, Mark wins the game.

In a change of pace episode, Mark begins to believe that Leprechauns are burying gold on the estate. Ignoring Mark's outrageous claims, Hardcastle concentrates on preparing the estate for an upcoming magazine contest. After Benny, Mark's mechanic, is assaulted by a group of men for information about a group of little people, Hardcastle admits that there may be some truth to Mark's Leprechaun story. That night, Mark and Hardcastle set a trap for the "Leprechauns". The trap works and Hardcastle captures the men who have been hanging around his estate. As the judge discovers, however, the little people are not Leprechauns but rather circus performers. Confronting the performers about why they are hiding out, Cluracan, the groups leader, explains that they are fleeing from communist agents that want to return them to their home country as well as Marvin, a circus promoter that had promised their services to Circus Maximus. As for the mysterious gold, Cluracan reveals that it is his family's money. The next day, communist agent Ivan and his men come to the estate disguised as employees of Ladies Garden Monthly, the magazine sponsoring the contest Hardcastle has entered. At the same time, Marvin and his men sneak onto the estate. With the circus performer's help, Hardcastle and McCormick manage to stop the agents as well as Marvin and his men. Later, Mark's continued suspicion that Cluracan's group are secretly Leprechauns seems to be confirmed when a rainbow leads to a mysteriously repaired Coyote.

While driving through Arizona on his way home from Las Vegas, Mark is surprised to hear the voice of Nick Damion, a rock deejay he idolized in his youth, on local radio station KKSB. Back in California, Hardcastle is working on a dedication for the Pioneers of Music Hall of Fame Museum. Hearing that the Museum needs a master of ceremonies, Mark suggests Nick Damion. Returning to Arizona, Hardcastle and McCormick try to learn something from Jeannine Alexander, KKSB's manager. After helping Damion, who has been using the alias of Joe Cross, out of a fake drug charge, Mark convinces the deejay to return with him to California. Trying to find out why someone tried to frame Damion (as well as why the deejay originally went into hiding), Hardcastle begins to investigate Kello Records, a company that had received a great deal of air time in the deejay's old radio show. At the same time, Damion, who had gone into hiding after discovering that music executive Joe Kello had killed a singer named Danny Phillips to cover up a payola scheme, realizes that he needs to go public with the story. Hardcastle's investigation proves partially unnecessary for the case is resolved when Damion publicly accuses Kello at the Museum dedication. Afterwards, Damion is shocked to discover that Hardcastle has uncovered proof that Jeannine is working with Kello. As the series' penultimate episode ends, Damion gets a new deejay job at a Los Angeles station.

Innocently given a friendly kiss by a woman named Aleeya "Ali" Casir, Mark unwittingly falls into the middle of a major international incident: Assuming that Mark is the American his daughter has been living with, Sheik Abdullah Casir, Ali's father and the leader of an oil rich mid-eastern country, decides to take whatever steps are necessary to protect his son's honor. As a result, Casir orders his Americanized daughter to marry Mark. Meanwhile, Hassan and Rabin, Casir's sons, begin to set up a drug dealing operation. Hoping to maintain friendly relations with Casir, the State department approaches Mark and "requests" that he marry Ali. Although Hardcastle tries to explain to Casir that Biff Anderson, Ali's real boyfriend, would be more than willing to take Mark's place, Casir, having already made an official announcement, is unwilling to change his plans. Forced to follow through with the wedding, Hardcastle, having learned about Casir's drug dealing sons, decides to use the ceremony as an opportunity to expose Hassan and Rabin. Confronted with his sons' guilt, an angered Casir vows to spare himself grief by staying out of his children's lives. As such, the wedding is canceled. Later, Mark is amused to hear that Ali has left Biff to marry a 35 year old television executive.

Cleaning out his shed, Hardcastle comes across an old trophy belonging to Teddy Hendrix, his college roommate. Deciding to visit Teddy, who is now a basketball coach, Hardcastle walks into an attempted kidnapping. Since Teddy flees the scene before he has a chance to confront him, the judge visits his old friend's wife. Thanks to Fran Hendrix, Hardcastle discovers that Teddy has been having a disagreement with a man named Roy Barlow. Realizing that his best chance of solving his problems lays with the judge, Teddy decides to tell Hardcastle about how he has been fixing basketball games. Agreeing to help his friend come clean, Hardcastle arranges a meeting between Teddy and the district attorney's office. Before Teddy can testify, Fran, who has secretly joined forces with Barlow, lures her husband into a trap. Meanwhile, Fran also helps Barlow capture Hardcastle. Thanks to Mark and their old basketball team buddies, Hardcastle and Teddy are rescued. Additionally, Mark and the former team members capture Fran and Barlow.

Questioning his maturity, Mark decides to trade in the Coyote for a more conservative car. To his surprise, his credit application is rejected due to an $18,000 default. Investigating, Mark discovers that his name was used in a real estate deal put together by Melinda Marshall, the girlfriend that had helped put him in prison. (As revealed in a flashback sequence, Mark, having foolishly placed his car in Melinda's name for insurance purposes, was arrested for stealing his own car.) Hoping to clear his credit record, Mark pays a visit on Melinda. Confronted by Mark, Melinda reveals that she had faked the real estate contract in order to win a car. When someone tries to steal the car Melinda won, Hardcastle realizes that there is something more going on than a simple real estate deal. Hearing that Melinda works for Ted Rubin, a man in his files, Hardcastle realizes that the real estate company is running a land fraud scram. Realizing that there is probably something hidden in Melinda's car, Hardcastle and McCormick conduct a search. As a result, they discover valuable stamps in the car and learn how Rubin has been transferring his money. Although Rubin arrives at the estate ready for a fight, he is captured thanks to the timely intervention of the FBI agents that had been investigating him. [During this episode, both Mark and Hardcastle have extremely subjective recollections of Mark's original trial.