Yokas struggles to survive her gunshot wound as her husband Fred craves revenge. Bosco feels remorse over what went down. Doc is asked by a burned firefighter to let him die.
Bosco feels unwelcomed by his fellow officers. Yokas wakes up to realize that she is paralyzed. Doc takes Taylor's death very hardly and finds himself mute at the funeral when asked to speak. Kim tries to find out more about Noble.
A van carrying Chinese immigrants also brings with it the plague and when one of the immigrants goes missing, it's up to the members of the watch to try and find them and halt a potential outbreak.
Doherty feels unaccustomed to his new role as a Lieutenant in charge. A rap star causes trouble for officers when he has his posse attack burned CD sellers. Yokas contends with physical therapy.
Sully tries to protect a very tough-minded judge who doesn't want to follow the rules of protection and may prove deadly to Davis. Cruz goes out on another undercover assignment to bust prostitution.
Sully continues to run protection of a judge who is the target of bombing attacks in the days before she presides over a huge murder trial. Cruz's mission against the person who violated her while undercover prevents her from performing a task crucial to said murder trial. Yokas seeks psychological help over the pain she feels, the source of which doctors have been unable to identify.
Davis and Sully take on the bomber who's been attacking Judge Halsted. Cruz' vengeance against her attacker is thwarted by the prostitution ring bust. Sully and Halsted warm to each other. Yokas reflects on her life before the police force. A public bus runs into one of the squad's ambulances.
The chase for a drug-dealing, murderous biker involves Cruz, Bosco, the FBI and a deadly stand-off. Doc joins up with Carlos on street patrol even as Carlos receives bad news about his daughter.
Bosco and Monroe try to protect a small businessman from mafia interference, but their initial efforts yield poor results. Carlos seeks a bone-marrow donor for his baby. Doc's assistance in this search leads to national coverage and Carlos receives a call from the baby's absentee mother.
Sully saves an orphan girl from a fiery blaze. Monroe canvasses the streets looking for a hard-to-find toy for her nephew. Carlos keeps his distance from a man claiming to be his brother. Doc finds the holidays depressing and lonely.
Boscoe and Monroe respond to a distress call to find a bleeding man with a strong desire to go home. Other officers and watch personnel arrive on scene and try to figure out exactly what has occurred.
Men posing as police officers ran criminally rampant through the city bringing paranoia to both the public and the officers themselves. Kim and Doherty decide to hide their relationship. Monroe tries to help a boy who saw his mother being attacked.
Even as Kim and Doherty's romance is rekindled, it is endangered when Doherty is trapped in a firey blaze. Monroe butts heads with Cruz over a murder confession. Doc worries about the longterm health of his station when a new captain takes charge.
Bosco's emotional state over a mobster's interactions with Bosco's mother leaves him vulnerable to attack. The new fire chief lets Kim know his plans to send the paramedics packing from the station. Carlos is visited by his long-lost brother. Doc shows an upbeat side in throwing a house party.
The firehouse is taken over by a firefighter who cracks under the pressure of their job. Bosco finds himself similarly made hostage by Nardo.
Bosco's brother tips him off to an ecstasy dealer bust. A psychiatrist tries to measure the emotional toll of the firehouse shooting.
Cruz trails after Bosco's brother after believing that he's linked to the death of an officer. The fire department continues to fall under the scrutiny of the visiting psychiatrist who hopes to discover the full scope of Doc's firehouse meltdown.
Monroe, plagued by guilt over the crime committed with her gun, gets into a car accident which kills a child. Yokas finds amusement in Cruz's entanglement with a new firefighter. Davis balances the LSATs and his need to comfort Monroe.
Yokas, Bosco and Cruz try to hit Ecstasy dealers but find themselves in each other's way. A fire breaks out at a rave party with both partygoers and medical personnel inside.
Bosco has reservations about his brother's lawyer and Yokas believes the lawyer's daughter has been abused. Sully discovers the life behind the man who used to serve him at his diner only after the man is killed. Davis tries to help Monroe adjust to being back in action.
The headless torso discovered by the police shares a personal connection to someone on the Watch. Yokas is taken back by the child abuse case involving a hospitalized mother and a jailed father and her involvement in the case may harm things on her own home front.
A man who holds the police responsible for the death of his son decides to take the lives of officers, most especially Cruz and Bosco who he holds most responsible. Drug raid crews are bombed. The funeral home with Bosco's brother's wake has a bomb driven into it by car, but they stop the driver from activating it.