Bosco roams the city looking for Faith, and finally tracks her down just as Faith manages to carry Fred out of the building after rescuing him from the elevator. After they race him to to Mercy, an overwrought Faith lashes out viciously and unfairly, first at Proctor and then at Bosco. As painful as her words are to hear, Bosco realizes the truth be

Bosco gets a temporary assignment working with a tough female sergeant; Fred is strangely calm in the face of the prospect of a triple bypass; Doc hears shocking news from Philadelphia; Sully learns more about Tatiana's past; Davis is forced to deal with his newfound fame.

Yokas and Bosco try to find a missing boy whose parents think has been taken by a registered sex offender; Sully prepares to be questioned about his wife's background

Doherty, riding on his motorcycle, is first to arrive at a multivehicle collision; Taylor is hit by a car; Tatiana goes to see Chevchenko, and tragedy ensues.

Chevchenko has Tatiana's son killed; Fred comes home from the hospital; and Davis gets a job offer.

Chevchenko has Tatiana's son killed; Fred comes home from the hospital; and Davis gets a job offer.

When a fire breaks out in the supermarket where Bosco and his mother Rose are doing some late night shopping, Bosco rescues most of the shoppers but cannot save a young mother when she goes back inside to retrieve her purse. After Jimmy tells him that the fire was probably deliberately set, Bosco is convinced that he saw the arsonist in the crowd outside after the fire. Sgt. Cruz gets Bosco and Faith assigned to the Anti-Crime Unit for a few days so that they can track the guy down. At the scene of another supermarket fire the next night, Faith takes down license plate numbers, Cruz photographs the crowd and cars at the scene, and Bosco nabs the man he saw in the crowd the night before. The man turns out to be a fire buff, but Faith and Cruz's work bears fruit and they find their arsonist -- the son of Doug Maple, an NYFD arson investigator. A depressed Sully is still on leave, drinking too much, and sleeping on the couch at Ty's and Carlos' apartment; Doc connects with an attractive

Emily discovers just what Faith's job entails and how much her mother loves her when they are taken hostage during a bank robbery, and Faith risks her life to save her daughter.

Bosco is dismayed as he watches Cruz go to the extreme lengths of planting drugs, frightening children, and faking a dying declaration in their attempt to arrest the drug dealer who killed another dealer and then tried to to kill the 12 year old boy who witnessed the crime; Nancy tells Ty that she's ending her relationship with Hancock, and gives Ty the ammunition he needs to get out from under Hancock's thumb and back to duty at the 55, as well as getting Sully's suspension from duty lifted.

Doc supervises a new paramedic on her first day; Carlos is arrested after a teenaged patient accuses him of molesting her; Bosco and Faith search for an escaped prisoner; Sully and Davis team up with fire and EMS to save construction workers when their scaffold collapses; in the aftermath of the bank robbery, Faith is troubled when Emily asks her how many people she's killed in the line of duty.

Sully's stopped drinking, but his poor attitude remains; Carlos gives his two week notice; a blizzard blankets the city and the squads are called in early; an understaffed Doc defies orders and puts Carlos back on the street as the squads are kept busy rescuing victims of the storm; Faith's initial wariness about Emily's new boyfriend Eric turns out to be well-founded when he is brought into Mercy after an overdose of Special K, but doesn't remember where he left Emily after she also got high; Faith, Bosco, Sully, Ty, Doc and Carlos go out to search for Emily, and rush her to Mercy after she's found in critical condition; Faith and Fred blame each other for letting Emily go out with Eric.

As Faith waits for Emily to awaken from her coma, she blames everyone but her daughter for the overdose and reflects on the substance abuse problems in her family; after Cruz's sister is brought into the hospital with an overdose, Cruz gets Sully, Ty and Bosco to look the other way on any possession charges and sets off with Bosco to find the location of her supplier's meth lab, where they end up in an inferno when the dealer sets the house on fire; Kim is reluctant to give a statement in Carlos's case because she's feeling pressured to lie to save his career.

As she keeps vigil by Emily's bedside, Faith recalls her first days at the Police Academy and the beginning of her friendship with Bosco; the fire squad rescues Bosco, Maritza, and a very pregnant Linda Barnes from the inferno, but Lettie Cruz succumbs to her drug binge before they can reach her; Emily is released from the hospital and takes responsibility for her overdose; Bosco tracks down Gary Barnes with Linda's help; Maritza and Bosco's relationship goes to a new level when he attempts to comfort her on the lost of her sister; Kim finally testifies before the review board and stands up for Carlos.

Faith rebuffs Bosco's attempt to apologize for lying to her; the fire squad extricates a driver impaled after crashing into a store; after Doc makes an impassioned defense of Carlos before the review board, a re-energized Carlos goes back out on the street; Sully's job performance continues to decline as he neglects to keep an eye on a woman he was supposed to be guarding, and she snatches her critically ill baby from Mercy's E.R.; after they discover that the woman is mentally ill, Ty takes a multi-story tumble while trying to prevent her from jumping off a roof with the baby; Faith is stunned when an initially reluctant Emily is eager to continue visiting a drug counselor; Ty catches Sully drinking in the R.M.P. and seeks advice from a union rep; Carlos loses his job as part of the department's settlement with the West family.

Bosco and Faith chase after people who have stolen money from a crashed armored van. Kim meets a journalist. The girl who accused Carlos attempts suicide, and the truth comes out.

Kim is invited to a party by Noble. Noble is arrested through an undercover operation. He becomes an informant and helps Cruz and Bosco bust a Meth ring. Faith officially requests a new partner. Emily and Faith face off about Eric.

Cruz's desire to find the ring leader of the Meth ring puts Bosco in a uncomfotable position. Faith tries to improve her relationship with Emily and also gets a new partner, Sasha, at work. Noble is released and sets up a new date with Kim.

Although Dade encourages him to keep quiet, Bosco tells Swersky everything that transpired with Maritza, Noble, the death of Willie G, and the shootout in Noble's hotel room, and confesses that he killed Noble after Noble pulled out a gun, Faith was shot by Maritza, and that he grazed Maritza's head with a bullet to keep her from killing Faith; wracked with grief that his wife has a bullet next to her spine, Fred attacks Bosco and threatens to kill him when he discovers that Faith became injured while she was helping her partner out of yet another jam; a critically injured Lt. Johnson, in excruciating pain and with only hours to live, begs Jimmy and Doc to ease his suffering; overwhelmed at the sight of Lt. Johnson's wife lashing out in heartbreak and anger, and her husband's horrific suffering and imminent death, Doc sadly helps out his boss one last time; Swersky has Maritza arrested when she refuses to tell him what happened during the shootout; Bosco learns that Noble was working f

On his last day on the street, Doc's guilt and grief over Alex's death emerges as anger towards everyone he encounters, especially Eugene, the new paramedic trainee whose place Alex took the day she died; Kim becomes frantic as she fears that she have been exposed to HIV after having unprotected sex with a drug addicted Noble, and Jimmy agrees to accompany her when she gets tested; Swersky goes to bat for Faith by creating the opportunity for Bosco to talk to her before she's interrogated by I.A.B.; Carlos is less than thrilled when he discovers that Kim is the new supervising paramedic and Jimmy has been promoted to take over Lt. Johnson's position; Bosco returns to work and faces a hostile reception from the squad for ratting out Maritza; Faith awakes to discover that she's paralyzed; Maritza refuses to let Faith off the hook for shooting her until Bosco tricks her into recanting her story; Faith thanks Bosco for keeping her out of jail and saving her job, and then tells him to get l

Yokas clashes with her mother over her recovery; Maritza is back on the job, but unhappy that she's back in the bag and handing out parking tickets; Ty and Sully discover a truck carrying sick illegal aliens and end up scouring the city to track down one of them who escapes after it's determined that the aliens have a highly contagious and potentially fatal disease.

Sasha, Bosco, Sully and Ty get on the case of a malicious rapper. Ty considers returning to law school with the help of Sully. Jimmy struggles with his new position and his relationship with his co-workers when he makes a big mistake during a fire drill. Faith gets a physical therapist.

Over her protests, a judge marked for execution is placed under a protective detail and gives Sully and Ty a scare when she slips away to get a cup of coffee; Levine uses an unorthodox way to get a patient's mind off his pain; when no physical reason can be found for Faith's intense pain, her doctor refers her to a psychiatrist; Kim is livid when Doc gives her an official letter of reprimand for disregarding field regulations just the way he did several times; in an effort to get out of the bag and off the street, Maritza convinces Swersky to let her set up a sting operation to catch a chiropractor who's fronting for prostitution, and pays a terrible price for continuing her ""lonesome cowboy"" approach to apprehending criminals.

The news that Faith is repartnering with Bosco outrages Fred; Bosco overcomes his initial wariness about his brother's claims of sobriety after the tip Mikey gives him about Ecstasy dealers leads to a solid bust; in the wake of the hostage situation, the department shrink sent to debrief the house elicits a range of emotional reactions from Kim, Carlos and Holly as she reveals that Doc is in the Bellevue psych ward on a suicide watch, and that the toll of 9/11 and its aftermath may be at the root of his collapse; when she investigates the murder of an Ecstasy dealer outside a rave, Maritza discovers that the motive may be a turf war between rival dealers; Bosco is distraught when Maritza informs him that the evidence points to Mikey's being a major Ecstasy dealer who used him to eliminate the competition by providing the tip that lead to the raid; Bosco and Maritza set out separately to find Mikey; tragedy occurs when Maritza and Dade pull over Mikey's car outside a rave.

Distraught over losing an appeal to her suspension, Sasha gets into a car accident that claims the life of a young child; Sully and Ty take the L.S.A.T.; tensions flare between the cops and the firefighters when Maritza goes after J.D., the newbie firefighter, who turns out to be an ex-cop who ratted out Maritza's former partner for stealing drug money; Faith and Fred are still at odds over her return to work; Walsh is promoted to lieutenant; Ty watches over a devastated Sasha, who's racked with guilt over the car accident, Doc's shooting spree, and the events surrounding the deaths of Tanzi and Nardo; J.D. gives Faith and Bosco important evidence he discovered as he put out the fire resulting from Sasha's car accident, which leads the cops to uncovering the basis for the accident and exonerating Sasha.

Tensions still run high in the Yokas household; Lester preps Bosco for Mikey's hearing, and then pulls a switch when he cross-examines him on the stand, leading to Mikey's getting RORd; Sully realizes what a toll the job has taken on him by his reaction to the deaths of three people in a robbery at the restaurant where he eats breakfast every day; Faith and Bosco answer a call which leads them to Lester's house, where they find his daughter not breathing; Sully tracks down and arrests the restaurant murderer; after Dr. Hickman tells Faith and Bosco that Lester's wife and daughter have been severely beaten, Lester is arrested; Sully gets his LSAT results; Ty and Sasha get closer.

The Boscorelli family suffers a tragic loss at the hands of Donald Mann, who blames Bosco, Faith and Maritza for the death of his son in a high-speed chase; the Yokas family heads off in different directions; the Martin family splits apart into separate jail cells for the parents, and a return home for Rebecca to the mother from whom she was stolen as an infant; the paramedic family at the 55 gets a new member, Grace Foster, which makes no one involved very happy.

Faith gets an earful from her daughter for not being around, and discovers that Emily's decision not to attend her mother's promotion ceremony was calculated to drive home a point about all the events Faith missed over the years; Finney threatens to blow Sasha's cover if she doesn't get the goods on Maritza; Sully and Sasha get more than they bargained for when they investigate a domestic and discover a decomposing corpse in the apartment directly above the quarreling couple, leading Sully to teach Brendan a lesson about the less glamorous aspects of police work; starting her career as a detective by partnering up with Jelly, Faith pursues her hunch that there's something more to what appears to be a simple suicide, and uncovers the deceased's plan to commit murder with a mail bomb; Grace teases Carlos about dating Holly, while expressing some interest in Brendan; Ty tries and fails to get more information from an uncooperative Sully after Brendan tells Ty that their fathers and Sully

Internal Affairs drops the bomb on the envelope-pushing Detective Cruz as she is taken away and struggles to survive in jail, while Captain Finney drills Detective Yokas for information that will nail Cruz - but the torn cop secretly knows that she pulled the trigger on a career criminal that frames the case against Cruz. Officer Sullivan reveals more about his running feud against Finney and his rookie son. Carlos and Levine keep getting called to help a suicidal woman. Bosco's condition changes.

Sasha anonymously slips Ty the I.A.B. file on the cover up of his father's death; Faith visits Bosco and lets him know how much she misses having him for a partner; Sully bristles at being partnered with Brendan; Faith learns a hard lesson about good detective work when she lets herself get hoodwinked into acting on prejudice and ill-informed assumptions in arresting an innocent man for the death of a pregnant Muslim teenager; Brendan and Grace decide to start over and take their relationship along slowly; after Ty reaches out to exactly the wrong person in the department's top brass to uncover the truth behind his father's death, Finney sets the stage for letting Ty know about Sasha's I.A.B. assignment and threatens them both if they continue with their investigations; Fred gets custody of Charlie and Emily agrees to live with Faith; Sully pursues his options on coming forward about Ty Sr.'s death; Brendan once again single-handedly rushes to the rescue to prevent a suicide.

Cruz teams up with Rice to track down the terrorists associated with the possible dirty bomb.

Cruz connects the dots that link Marcel Hollis to the murder of Darren Maddox, while Marcel begins to organize a street war against the 55th Precinct. Elsewhere, Yokas, Sully, and Bosco track a missing teen to a vampire cult.

Monroe and Bosco deal with an angry mother on welfare who shoots up the welfare office, Davis and Finney stake out a man and take down a prostitution ring, Faith deals with Emily, Cruz and Monroe recieve bad news about their health.

Finney and Davis are seriously injured in a car accident during a traffic jam, which was caused by a man trying to kill two people, and he succeeds. Emily's life is in danger when she falls in with the wrong crowd. Carlos buys an engagement ring for Holly.

Faith negotiates the end of a live on TV hostage situation. The leader of a vampire cult holds Emily hostage until Bosco saves the day. Cruz attempts to negotiate a deal with a gangbanger to end the war on the 55th Precinct, but instead, he organizes his troops to attack.

The series concludes with the gangbangers taking out their assault on the 55th Precinct. After some grenade explosions, the precinct is destroyed. Cruz knows that Marcel Hollis is behind the attack, and she takes his life, as well as her own. Carlos proposes to Holly, and they are married. Everyone receives their reassignments, and Sully retires. In the last few moments, Sully narrates a look into the future.