The SIU try to track down a couple of death metal fans who shot Harvey and have others on their hit list. Stacy and Nash meet a woman who claims to know Nick, and discover some secrets about Nick's past. Joe finds Evan and Cassidy in a compromising situation, which lead to their relationship being revealed to Nash.moreless
The SIU try to track down missing armoured cars. Joe and Nash do an off duty case for a pro football player, that involves them looking for a fan. Cassidy and Evan discuss telling Nash about their relationship. Nash and Nick fight over a dentist appointment.
Lynette finds herself the target of a Chinese mob, trying to locate a missing money plate that they suspect were sent to her from an old flame. Joe's father is in town, and decides to do a little investigating himself, when he overhears a neighbors conversation.
The SIU desperately try to find who is behind producing a very deadly virus. A woman shows up, claiming to be Joe's daughter. Evan and Cassidy start sneaking around together.
A dead woman is found in Bettina's bed, and all signs point to him as the killer, especially when he seems to be withholding information. Nash is convinced that he is innocent and tries to prove his innocence. Joe tries to track down a man who has stolen his identity and is living a life of romance. Inger assumes that Joe is cheating. Cassidy asks Evan to be her friend's date in a double date, but things don't go as planned.moreless
An investigation of a shot up car with five dead gang members, and an alive rival member in the trunk, leads Nash and Joe to a drug dealer from a rich family. Evan and Bettina go undercover at a transgendered beauty pageant to find killer that is a woman, pretending to be a man in drag. Harvey runs into an old flame.moreless
Kelly is back in San Fransisco and the victim of an attack. Nash and the SIU discover that Kelly's boyfriend has ties to an Irish terrorist group and he is seeking revenge against the leader, while the group plans an attack. Joe and Evan get a side job looking after a party-minded Arabian prince awaiting a heart transplant.moreless
Nash and Joe team up with a tough-talking NYPD Special Crimes Detective in order to track down a famous fashion model's deadly stalker. When Evan's one-night stand steals his badge, he turns to Harvey for help tracking her down, however he knows nothing about the woman. Nick and Lynette get arrested for assault against a local politician, and decide to fight the injustice.moreless
Bettina forces Nash to take a ten month vacation, and drives everyone at SIU nuts. Nash tries everything he can to get his job back. Despite being on leave, he winds up helping with the investigation of a group of robbers hitting seemingly random targets. Nick races Mr. Woody against Bettina's mom's horse.moreless
Geraldo Rivera comes to do an interview with Nash and Joe. At first they have to hold things off while Nash recovers from having his drink spiked while undercover. Once he comes through it, they become curious as to how Geraldo knows so much about their personal lives. The SIU also has to investigate what starts as an open-and-shut self defence case, which becomes more complex the deeper they dig.moreless
A million dollar bounty on Nash's head triggers an onslaught of attacks by a series of ultimate fighters. Michelle, Evan and Harvey are on a stake out, trying to trackdown a rapist who meets women online. Nash is convinced that Cassidy's new boyfriend in gay.
Nash and Joe get in a car chase, and afterward discover that there was three million dollars in the backseat. They soon learn that there was supposed to be six million. Bettina is now the head of S.I.U. and is determined to pin the missing three million on Joe, who was at one point alone with the money. Harvey bumps into a woman he once arrested and they start a relationship. Evan worries that Harvey may be getting conned.moreless
A former flame of Nash's who conned him, is back, and is the key to locating plutonium that has been smuggled into the country. Joe decides to try and market his family salsa, but as usual, things go awry.
A convicted murderer is accidentally released from prison, and seeks revenge on those who helped put him away; and Michelle happens to be one of them. Joe gets an off duty case of blackmail, and Nash refuses to help him, so Evan becomes his new partner.
Nash gets a call from a reporter wanting to talk to him about his long lost and thought-to-be-dead brother. When he goes to meet her she gets murdered. While investigating the case he comes to learn that his brother is not dead. Lisa's sister comes to town to stay with Cassidy.moreless
The SIU try and locate an anti-government sniper, targeting local government businesses. Michelle gets in hot water when she shoots a suspect, who she believes has a gun on a roof, but there is no evidence of one. It's Halloween and there is a Blue Flu, forcing the SIU to also deal with local police work. Joe tries to find a specific hard-to-find costume for Lucia, after the one he has gets ruined.moreless
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, who happens to be her boyfriend. Stacy becomes concerned that Nick is being turned into a lab rat at the university where he has volunteered for a research study.moreless
After narrowly escaping an explosion, Nash suffers from short-term memory loss. He tries to figure out what he knew about an undercover case he was on, but the SIU was in the dark as much as he is. Michelle joins the SIU, and Evan is accidentally recorded talking about how much he likes her on one of her recording devices. Cassidy wants to tutor an ex-con.moreless
The SIU try to track down a mentally ill serial killer, who uses Sherlock Holmes stories as backdrops for his murders. Joe, on Nash's recommendation, hires a nurse to take care of Lucia. She is great with the baby, but drives Joe and Ingur crazy. Evan worries about a police test that everyone in the SIU must take.moreless
Nash and Joe track down a former mob underboss who's murdering San Francisco criminals. Inger has to go out of town, leaving Joe with the baby. Nick has a new girlfriend, but she has some secrets.
Nash and Joe enlist the help of a prison inmate whose former partner is willing to kill anyone to find missing money from a job they pulled years back. Lisa's new business partner isn't what he seems, so she enlists the help of Joe to investigate him.
Nash and Joe try and track down stolen FBI weapons from two car thieves. Nash reluctantly agrees to go on a blind date with Joe's nanny, but winds up enjoying himself. After his car is destroyed by one of the stolen weapons, Joe looks into buying a new one.