Mercy's new E.R. attending gives the cops and paramedics a hard time while ignoring Carlos's attempts to hit on her; Doc is saddened to hear that Jerry has decided to take a disability retirement; Jimmy is upset when Joey goes to Bobby first after he becomes ill as a result of Jimmy's letting him overindulge in sweets; Jimmy and Bobby take out their conflict over Kim and Joey in a game of one-on-one; Sully and Ty arrest a purse snatcher who will do anything to stay in jail once he discovers that his victim's son is a mobster; Faith hands out street justice to a gangbanger responsible for the deaths of two little boys.

Sully and Maggie reconnect; Bobby visits his brother Matty and tries to prepare him for his release from prison; Sunny asks Kim for a place to stay and runs away when Kim refers her to a shelter; Carlos hits a pedestrian with the bus; Faith and Bosco investigate a grave robbery and ponder immortality; Jimmy rescues a new recruit who is trapped under a collapsed ceiling in an apartment fire; Bobby takes Doc's advice and tells Kim how he feels, only to learn that Kim feels she isn't good enough for him; Sunny ODs and Bobby helps a saddened Kim find out her real name and hometown so that her parents can be notified; Sully's approach to ""problem solving"" goes horribly awry in a domestic dispute; Carlos and Doc come to blows over Doc's training methods, forcing Morales to break them up; Sully learns that Ty has good instincts, enabling them to save a teenage girl from a sexual predator.

Ty is worried about Sully's dating Maggie; Faith and Bosco lose a witness who turns out to be the perp in a homicide; Bobby prepares for Matty's release from prison; while driving the bus, Carlos collides with a pregnant driver and later attempts to revive the baby she delivered prematurely after Sarah pronounces it dead, unaware of the consequences for the parents; Jimmy rescues a boy from a tree; Bosco and Ty take issue with Sully over his handling of a belligerent collar.

When he goes on his first raid, Davis inadvertently endangers a young boy he is trying to help; Doc begins to think that the overdose his father took may not have been accidental; to get a critically ill woman to the hospital, the firefighters knock down an apartment wall and lower her out a high story window.

An explosion in a building about to be demolished leaves men trapped inside, forcing the firefighters to make terrible choices; Fred's drinking problem escalates; Doc cancels his date with Brenda.

Jimmy's failure to watch the firehouse door leads to tragedy; Morales, devastated by the loss of a young patient, reaches out to Doc for consolation; Sully's first partner commits suicide, prompting him to seek out Maggie and reflect on where his life has gone; Bosco tries to buy a '67 GTO from a homeless man; and Bobby continues to do whatever he can to get his mother to reconcile with his brother.

Ty spends the shift on foot patrol with Candyman and discovers some disturbing facts about both his late father and Candyman; romance blooms between Doc and Morales after Doc's father tells him to get on with his life; Matty's attempts to make amends for past misdeeds have upsetting outcomes; Jimmy has an unexpected and unpleasant visit with his bookie; Faith clashes with the mother of a missing girl; Sully puts in a good word for a hit-and-run driver to a completely unsympathetic D.A.; and Bobby is crushed to learn that Matty was an unwitting accessory to a felony homicide.

Faith, Bosco, Sully, Ty and Candyman race through the neighborhood on foot in pursuit of a trio of Uzi-armed thieves; Candyman risks his life to save Ty; Bosco's cold refusal to get medical assistance for one of the perps leads to the robber's death; Ty searches for the truth about his father; Bobby's mother tells the police where to find Matty, who desperately pleads with Bobby to give him some getaway money; Bobby agrees, but begs Matty to turn himself in; Matty gets high and takes off, leaving Bobby crushed and seeking consolation from Kim; and Carlos finds out about Doc and Morales.

It's Valentine's Day and Bobby and Kim have spent the night together; Bobby's confession of love leads Kim to realize that they've made a big mistake; after agonizing all day, she finally confesses and breaks Bobby's heart; seeking solace in a bottle, Bobby finds himself at a local bar next to a woman who has also been jilted that day, and they go off to her place; Fred drunkenly totals the car on the way to pick up Emily and Charlie; Faith arrests him and refuses to bail him out; when he finally arrives home, Faith has his things already packed and throws him out; Carlos tends to a girl who runs into a bus and then falls for him; the gay community is targeted by a gunman and a vigilante group forms to find the killer; Ty arrests a girl for auto theft who turns out to be Malcolm's sister; and Faith lets Bosco know that she is fed up with his bigotry.

Dealing with the aftermath of gang warfare, Doc and Carlos disagree over reaching out to prevent an eleven year old boy from following his brother into a gang; Bosco's decision to turn the tables on two men who try to rob him when he's off-duty could cost him his badge when the two men turn up at the precinct to report the crime; as he continues his losing streak, Jimmy gets deeper and deeper into his bookie, which puts Joey in danger; Kim begins to worry about how much time she spends with Joey after he gets into trouble at school.

Yokas continues to have marital difficulties with Fred and, when she meets up with an old flame at the scene of a car accident, she finds herself very tempted to accept his invitation to meet him in his hotel room to catch up on old times. Doc's dad ends up in intensive care leaving Doc with some hard decisions. A perp accuses 'Candyman' of stealing money from him when he arrested him. Davis believes the criminal and is not sure how he is going to answer IAB's questions about what happened, even though he didn't see anything happen. The police station takes on the fire station in a basketball game.

Carlos falls behind in his studies and then hears some shocking news from Vangie; the cops search for a two-year old girl missing after her family is involved in a car crash; Bosco and Faith contend with a disabled man dealing drugs to children; Sully and Davis track down the alcoholic who attacked the pastor of Sully's church.

Doherty shows his bravery trying to save the mother of two young children from a fire. Meanwhile Bosco and Faith are out looking for the man suspected of starting the fire in the first place. Davis tries to set Sully up on a blind date and after her pimp beats up Malcolm's sister they try to find him before he kills the man who did it. Carlos' girlfriend problems escalate and Doc's relationship looks like going to the next stage.

Yokas and Bosco chase a carjacker into a multi-level garage. When the thief drives off the edge of the top level and crashes to the ground, Bobby risks his own life to save the driver. Much to the surprise of everyone who knows him, Bosco goes to the opera with Nicole and her parents. Carlos gets into trouble with his boss and Vangie. Sully and Ty go to help Candyman on a job, and Ty tells Candyman exactly what he thinks of him. Jimmy has news for Kim which surprises her, and annoys Bobby everytime Kim tries to talk to him about it.

Doc and Carlos are rescued by the firefighters when they get trapped in an eighteenth floor apartment with a patient who cannot walk; Ty comes to the end of his probationary period; Faith discovers that she's pregnant again; the firefighters come under fire from a madman when they arrive to fight a car fire.

A rapist attacks three victims; Yokas agonizes over her finances, her marriage and her pregnancy; Bosco's jealousy threatens his relationship with Nicole.

On the hunt for a robbery homicide suspect, the police shake down all young black males they encounter, igniting racial tensions throughout the city. The suspect in question turns out to be Puppet, whose younger brother was killed as a result of Puppet's gang activity despite Doc's attempts to turn him away from the streets. After he's shot by the cops and goes into hiding, Puppet solicits Doc's help by proclaiming his innocence. The ensuing lengths to which Doc goes to get Puppet to the hospital and save his life while avoiding the cops wreak havoc with Doc's relationships with both civilians and the squads.

A disturbing visit from his former high school girlfriend forces Doc to confront a horrible act he has hidden for years; Carlos struggles to pass a medical school qualification exam.

Bosco arrests a pedophile posing as a toy store Santa, and the grateful store owner returns the favor by helping Bosco and Sasha come to the aid of a man whose house is robbed of all his children's Christmas presents; after Sully and Ty save a young homeless girl from a fire, she rekindles Sully's Christmas spirit; Carlos receives the ultimate Christmas present when his brother arrives at the firehouse bearing the gift of being a perfect bone marrow match for Kylie, as well as the news of Carlos's real name and family history; Kim and Jimmy spend a romantic Christmas Eve together; Sasha's search for the perfect gift for her nephew gives Swersky the opportunity to play Santa.