As a result of a pension dispute, Joe Dominguez is forced to rejoin the force, and he and Nash track down a heroin dealer.

Nash Bridges and the SIU team respond to a bomb threat against Mayor Bobbie Werksman. In a tenement, they find the bomb, but accidently trigger the timer. Everyone rushes out in time as the bomb destroys the building. Nash is the last one to leave.

Nash investigates a judge's murder, and unwittingly triggers an Internal Affairs investigation. The Internal Affairs cops go bad, and only Nash Bridges and the SIU can stop them.

Nash has to deal with the fact that Joe may have 72 hours to live after being exposed to a deadly virus while Nash & Joe investigate a drug theft from a research lab.

A busload of San Quentin prisoners on their way to court is hi-jacked in downtown San Francisco. Nash has to track down two dangerous escapees, including a paramilitary activist who seeks bitter revenge on Nash.

Nash and Joe cut a deal with Carlos Casas, a gangland money launderer, offering him a new identity in exchange for his testimony.

Nash and Joe have a task of escorting a secret key witness from the Witness Protection Program to San Francisco to testify in an important SIU-related case. They fall under gunfire. Nash realizes there's a leak somewhere on the prosecution's team. He enlists the help of Stacy to protect them until he can solve who it is and get the witness safely to San Francisco. Cassidy is stood up for a date and decides to go out with J.J. instead.

Nash's sister, Stacy, is robbed, forcing her to come out of the closet as a lesbian. Nash deals with his own secret romance with Nick's nurse Whitney. The fallout from these family revelations takes place while Nash tracks down a kinky couple responsible for the robberies.

Hot on the trail of a murderous criminal from Chicago, Nash teams up with a KAREN DECKER, a cop from the Windy City who's in every way his equal: smart, competent-and yes, sexy. Sparks fly between them as they track down the visiting villain together -until, that is, Nash learns his newfound partner is not as perfect as she's led him to believe. Joe, meanwhile, hires a pet psychologist to cure what ails Nick's racehorse, Mr. Woody.

Nash solves murders in Chinatown and helps out an old friend, Cedrick Hawks, a professional gambler who is in San Francisco to clear up a bad debt.

Nash must protect Lynette (Suki Kaiser) from ruthless Hong Kong mobsters when she unknowingly becomes involved in an Asian forgery ring. When Lynette's old flame, Brian, mails her a flawless forgery plate for $100 bills, Nash must protect her from the brutal Hong Kong gangsters from whom the plate was stolen. When Brian unexpectedly appears at Lynette's door, their attraction is re-ignited, but he soon becomes the chief suspect in Nash's investigation into the forgery ring, run by an Asian crime syndicate. Meanwhile, Joe's visiting father (Ismael Carlo), a sheriff from New Mexico, drives Joe crazy with his meddling until he uses his own brand of Wild West sleuthing to expose a murderer in Joe's apartment building.

Lowlife Frankie Dwyer returns, this time importing Vietnamese women as sex slaves, as Caitlin goes undercover as the seller. Nash has a tooth ache and refers to Caitlin by his first wife's name. Joe is aggressively pursued by bodybuilder Spike; Evan bumps into Cassidy in his job as a parking lot attendant.