Willie Nelson plays Earl Dobbs, a convict who gets a furlough from San Quentin to help Nash and Joe catch his former crime partner.

Nash and Joe track down a former mob underboss who's murdering San Francisco criminals. Meanwhile, Inger has to go out of town, leaving Nash and Joe with the baby.

Nash, on the verge of closing a case, narrowly avoids getting killed in an explosion, losing a week's worth of memory as a result. With Joe's help, he has to retrace his steps, resolve the case, and deal with the various personal snafus resulting from his memory loss. Michelle joins the SIU.

Cassidy finds herself in the middle of an SIU case when she becomes the victim of a high-climbing jewel thief and Nash begins to close in on the suspect: her new boyfriend. Stacy becomes concerned that Nick is being turned into a lab rat at the university where he has volunteered for a research study.

Sultry criminal and Nash's ex-girlfriend Tamara VanZant resurfaces, this time as a player in a plot to sell stolen plutonium. Joe plans to make a mint by marketing a secret-recipe salsa that's been in his family for generations. Robert Rodriguez stars as Joe's commercial director.

Rick Bettina returns as the head of the S.I.U. Joe is accused of stealing 3 million dollars from a suspect. Harvey has a torrid affair with a woman he once arrested.

Geraldo Rivera comes to the SIU to interview Nash and Joe. Nash arrives at the SIU after having his drink spiked with acid by a biker couple; and there's a ""mole"" in the SIU feeding sensitive information about Nash to Geraldo, which he uses in the interview. Meanwhile, our SIU cops must solve a mystery which begins as a routine shooting at a convenience store.

Nash and Joe investigate several brutal drug-related gangland murders and follow a complicated trail of clues to a surprising suspect -- Bruce Sutcliffe, a multi-millionaire from a well-respected San Francisco family. When Nash discovers that Sutcliffe has been a major drug kingpin for years, he risks his job and his life to expose the magnate's secret life. Meanwhile, Evan and Bettina go undercover in a transgender beauty pageant to trap a blackmailing murderess who pretends to be a man impersonating a woman.

Bettina is accused of killing a high-class call girl. Only Nash can help Rick find out who framed him for murder. Meanwhile, a man masquerading as Joe has become a major romantic figure in town (with Joe's credit cards), much to Inger's chagrin.

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.

When the ruthless high school dropouts go on the crime spree, Nash's search for the couple leads him into an underworld of heavy metal rock and satanic worship. As the intensity of the crimes increases, Nash must race against time to stop the desperate duo before they murder all the enemies on their ""grudge list."" ; Stacy and Nash meet Nick's long-lost love from the war years; Joe finds Evan and Cassidy in a compromising situation.

Nash must stop a sniper terrorizing the city by shooting victims at random. A rat infestation forces Joe to confront his ""landlord,"" Nash, about the problem. Evan proposes to Cassidy, but in the wake of a serious traffic accident, Cassidy is left fighting for her life.

Nash and the SIU must re-open a serial killer's case file when a body is discovered and it appears to be Angel's. Bonnie, Harvey's ex-wife, returns with an interesting proposition. Joe and Caitlin square off as rival soccer coaches when their teams enter the playoffs.

Nash and Joe investigate a missing hockey goalie connected to the Russian Mafia with the help of kidnapper Tony B., who has lost all memory of the crime. Joe visits a fertility clinic when Inger decides she wants another child. Harvey and Evan shoot off the roof of the watch commander's brand new squad car and must get it fixed before he finds out.

An ex-cop is released from jail and seeks revenge on Caitlin who put him there. Nash teams up with Caitlin to capture him. Joe and Inger continue their efforts to become pregnant, discovering how difficult it is. Harvey and Evan go underground as wealthy conventioneers at a ritzy hotel bar to catch a follow-home robber.

Four robbers storm into a check-cashing outlet. They release tear gas grenades and rob the place. Nash, Joe, Harvey, and Evan respond to the silent alarm. Three robbers (who all turn out to be women) dump the cash into a getaway car (driven by another woman) and leave on foot. Harvey and Evan run into the getaway car, but let it go, not knowing that the robbers are women. Nash and Joe confront the fourth robber. Nash shoots him dead through the eye hole in his gas mask. The dead robber is Adrian Beltran; stolen is 100,000 dollars. The MO (modus operandi) is similar to a North Beach robbery crew from four years ago, who are now all in prison. Nash suspects Anthony Warrick, who ratted out the original crew. But Warrick retains heavy-duty lawyer Denise, and Warrick is clean with no connection to the dead man. While Harvey and Evan surveil Warrick, another robbery goes off. A trace of the tear gas grenades leads to Bunker Bob, but he only identifies the dead Adrian Beltran. A study of the

Handcuffed Skip Osaka jumps out the back of the moving 'Cuda. Nash and Joe give chase. Skip runs up a fire escape onto a power line. The line breaks, and Skip falls through a window. Nash and Joe place him in the trunk of the 'Cuda, and bring him to the SIU. A surprised Nash, Joe and Harvey discover the SIU barge is being towed away by a tugboat. The Head of the MCD, Reuben Banks, drives up and informs Nash the SIU has been temporarily shut down. The SIU is disbanded by MCD: Nash and Joe are assigned to Park Detail, Harvey to Homicide, Evan to Traffic, and Caitlin to Vice. At the Civic Center Park, Nash and Joe meet Colonel Culpepper, drug addict/transient, and Phil, the phony Vietnam veteran. The Colonel is shot dead in the park. Harvey and his new partner, Inspector Riley Webber, investigate the murder. Evan and Cassidy have set a wedding date. Harvey is best man, and he plans the bachelor party. Nash and Nick are informed, and Nash gives his blessing. Father Nick gives Cassidy her g

Nash and Joe meet Lyle who tells them the secret location the SIU barge has been towed to. Joe returns Lyle's chihuahua Ginger who has been held hostage in return for the info. A truck deliberately rams into a van containing three prisoners. Nash and Joe arrive at the accident scene, with Nash figuring out that a phony paramedic van has taken the three prisoners in a successful escape attempt. Nash, Joe, Harvey and Evan arrive at the empty and disconnected SIU. The Mayor has granted a one week reprieve pending the Police Commission hearing. If Nash and company catch the three escaped prisoners, the SIU will be saved. Head of MCD Reuben Banks daughter Gina's immunity deal is also dependent upon the return of one of the escaped prisoners - Gina's former boyfriend, Jimmy ""Shank"" Brasher. The other two escapees are Darnell Galloway and Elliot Wong. Gina is kidnapped by Brasher. Jake Cage of Fugitive Recovery is already on the case, beating Nash to interview Mr. Footman, owner of the stolen

Jake Cage and Caitlin go undercover to capture an international fugitive returning home for the wedding of his daughter. Nash and Joe steal a violin for corporate clients, only to have the violin stolen again by one of Joe's detective students. Evan gets involved with a street prostitute.

An embezzler with a twin, along with bumbling Rick Bettina, confound the efforts of Nash and the SIU to recover stolen city funds. Caitlin tosses Nash's baseball out the window after they miss their flight to Jamaica.

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.

Nash goes undercover as a hitman for a drug cartel. Nick's poker buddies plan a bank heist; Inger returns from Sweden with her mother; Evan gets his engagement ring back from Cassidy.

A married woman is murdered by her lover and his wife. Evan is beaten up trying to free his girlfriend/hooker from the clutches of a pimp. Joe takes Evan in, but Evan attempts suicide. Boz Bishop asks for a promotion at the detective agency.

Frankie Dwyer returns again, putting out a contract on Nash's life while smuggling heroin inside of tofu containers. Nash and Caitlin's relationship is strained; Inger sets up Nick with her mother Ulla; Evan is born again in a baptism.

Wearing his brother's uniform as a motorcycle cop and impersonating a police officer, a deranged man imagines and talks to his dead brother. Nash adjusts to his break-up with Caitlin; Nick fails his driving test; Cassidy asks Evan for help to move back into a Berkeley apartment.