Sully lives his worst nightmare as the police search the city for a man who is buried alive and whose kidnappers are involved in a fatal car crash; Kim and Bobby find an abandoned 4 year old boy wandering the streets; Sully's mother wanders off from her nursing home; Carlos adopts a deceased patient's cockatoo.

The ordeals of an elderly friend prompt Sully to consider his own loneliness; Alex regrets revealing that she discovered Jimmy on the eve of his wedding having sex with an old flame who happens to be Lombardo's current girlfriend after the news spreads like wildfire throughout the squad; Jimmy and Brooke get married.

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.

A secret threatens to destroy Jimmy's relationships at work and home; Sully makes a date with his pretty neighbor; Bosco gets violent after his mother is beaten by her boyfriend.

Bobby's attempt to keep Paulie away from drugs ends tragically.

Faith and Bosco hunt down the dealer who distributed a batch of lethal heroin; depressed over Bobby's death, Kim attempts suicide.

Doc is thrilled when Sarah accepts his proposal, but is stunned when she informs him that she's accepting a job offer in Philadelphia and wants him to relocate.

Ty, Sully, Bosco, and Faith rush to the scene of a school shooting; Sully and Tatiana ponder their future together; Kim continues to struggle with her depression.

Kim and Jimmy are having a custody battle over Joey. Boscoe and Faith are on a call of a possible terrorist threat, that ends up being an explosive event. Alex risks herself to save a little girl and is punished by Doc for it.

Doc is up for paramedic of the year and is being followed by a film crew. Doc may have made a medical mistake when treating a patient. Faith recovering from cancer treatment and on the job fails to back up Boscoe while chasing a suspect.

After seeing his young son Joey fall and break his arm in a playground accident, Jimmy fights through a burning apartment building to save a frightened boy of Joey's age. Meanwhile, a guilt-ridden Doc can't stay away from a recuperating teenager, Ryan Buckley, who was accidentally paralyzed while under Doc's care. Taylor is annoyed by a new probationary firefighter, Ken Prescott. Bosco and Yokas search for a drug addict who murdered his girlfriend.

Feeling betrayed, Doc angrily confronts his former friend, Jerry Mankowitz, an attorney's investigator who tricked him into confiding vital information about a pending malpractice suit.

The police officers sort through the carnage and count their dead in the wake of a shootout between rival gangs. While Faith tries to interrogate Fyodor Chevchenko, a ruthless Russian mob boss, Sully worries about the severely wounded Ty and regrets causing the incident. Tatiana chastises Sully for hassling her injured son. Faith worries about Gusler, her ineffective, frightened rookie partner and a weary Doc gets some unexpected, good news about his medical malpractice suit.

During the investigation of the gang shootout, the police officers are questioned and presented with evidence that suggests that Ross was killed by friendly fire; Carlos learns that Vangie is dead and that he is the father of the baby her sister leaves at the firehouse; on the first anniversary of Bobby's death, Kim quarrels with Jimmy over her visitation with Joey and confronts a female gang during a call; and Doc is visited by the father of a former patient whose debilitating injury may have been caused by Doc's error during treatment.

Bosco starts having panic attacks and goes to see a therapist, but it doesn’t work and later he turns to the only person who’ll listen. Carlos is discovering the trials of single parenthood and starts thinking about adoption. Faith is studying for the Sergeant's exam. However, her concerns about Bosco’s mental and emotional health cause her to fail, and this angers Fred, and he storms out of the house. But later, he sees Faith comforting a sobbing and weeping Bosco after Bosco admits that he couldn’t go back to the World Trade Center towers after they fell down.

Hopelessly in love with Kylie and concerned that she will lose her Filipina heritage if she is adopted by a white couple, Carlos considers raising her until he realizes that the couple can give her the sister, the grandparents, and the extended family that he cannot. Kim's preoccupation with her new PDA drives Alex crazy until they are able to use it to save a very sick man, thus redeeming themselves in the eyes of a hypercritical Dr. Peterson. Faith and Fred are still on uneven ground about the Sergeant's exam. In an effort to shake Chevchenko's tree, Faith and Sully execute a clever plan to disrupt the Russian's bookmaking operation which also opens the door to the possibility of the still-missing Tatiana's return. Bosco is cleared for duty, and he and Faith agree to be partners again as soon as he returns.

When a doctor comes to New York to search for the missing daughter of her drug-addicted sister, Faith and Bosco focus their attention on the child's stepfather, a New Jersey cop, after they discover that the girl was taken by a man in uniform; Tatiana returns home; Jimmy spends some quality time with Joey.

The crossover starts on ER S08E19 Brothers and Sisters

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.

Monty and Joy hook up. Miguel witnesses one drug dealer murder another, and becomes the dealer's next target. On his first day back at work, Sully rides with Faith, who is put off by his short fuse and bad attitude. When he leaves a prisoner unguarded and uncuffed, Faith tells him to go home because he's not ready to be back on the job. Sully gets drunk and goes to his mother's nursing home. Sobbing about Tatiana, he tries to batter down the door when the receptionist won't let him in and calls the police. After Hancock arrives on the scene, Sully mouths off to him about Nancy in front of the other officers who are there to take him home.

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.

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.

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

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.

Sully kills one of the perps and shoots the denotator out of the hand of Frank Morgan, the bomber; Doc goes ballistic when he comes upon the scene of an accident involving his old rig and a city bus, and physically assaults Eugene; Public Morals raids Dr. Chow's office, and Maritza is forced to reveal her rape to keep Thomas Warner from being released on a D.A.T.; Ty gets Frank Morgan to flip on Gary Barnes, and Barbara promises Morgan that she will make sure he gets the death penalty for killing her housekeeper and driver; Kim and Carlos refuse to back up Eugene after he files a complaint against Doc, prompting Eugene to quit; a distraught Faith, still plagued by flashbacks of the shooting, asks Fred if they can get out of the city for a family vacation; Warner confesses to raping Maritza while Bosco is transporting him to the Tombs; Carlos is horrified when Doc admits that he accosted Eugene at his house because he ""killed Taylor""; Bosco turns Warner over to Maritza, who gets her pay

Doc is demoted back to the streets and continues his downward spiral, presenting Kim with no end of problems as he lies about his demotion, resists her orders as the supervising paramedic, and deliberately runs down a perp with the bus; Barnes is shanked at Riker's for doing a flip on Buford; Carlos is devastated when Kylie is diagnosed with aplastic anemia and he's not a match for a bone marrow donation; Sully tries to deflect Ty's teasing about his relationship with Barbara by getting him to focus on their LSAT prep; after a horrific gunfight, Maritza finally captures Lettie's killer and decides to spare him so that he can suffer for the rest of his life in prison.

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.

When Sasha discusses taking the sergeant's exam with Maritza, Maritza reveals that she received her promotion meritoriously, not from passing the test; the police are on high alert after two women are assaulted and robbed by men posing as police officers; Kim and Jimmy decide to keep their blossoming romance quiet until Kim is pulled over by the impostors and narrowly escapes with her life with the help of Bosco, Maritza, Sully and Sasha.

Steeper exiles the paramedics to permanent fixed posts on the street, which upsets everyone on the squad except Doc, who refuses to let anything put a damper on his unusually upbeat attitude; Carlos is less than thrilled when Doc invites Christian to accompany them on a ride-along without getting the proper authorization; when Bosco goes after Nardo for his veiled threats against Rose, Nardo tries to set Bosco up to look like a dirty cop; Rose is fired after Bosco destroys poker machines owned by Nardo in the bar where she works; on the eve of her return to duty, Faith tells Bosco that she wants to repartner with him; Sasha's second thoughts about the plan she and Bosco hatched to repay Nardo for threatening Rose and attempting to frame Bosco turn out to be on target when Nardo flees after murdering two men; Doc and Sasha hook up after Doc throws a big party at his house for his co-workers.

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.

Wary of Lester Martin, the high-priced lawyer his father has found for Mikey and the deal he's attempting to broker, Bosco warns his brother to stay away from Maritza, but Mikey decides to disregard his brother's advice and makes a deal to become her informant; for good measure, Bosco threatens to kill Maritza if anything happens to Mikey; Sully teases Ty about his budding relationship with Sasha; Faith and Bosco strike a deal with Laura, who also has no love lost for Maritza, to protect Mikey by helping her nab the drug dealers before Maritza gets to them; J.D. offers Kim a ride home, but stops off first at a rave that both Anti-Crime and Narcotics have staked out, thanks to information Mikey gave them; when some bad ecstasy begins to take a rapid toll, the paramedics call for backup, which prompts Maritza and her detail to storm the building; after an arsonist lobs a Molotov cocktail into the crowded building, Faith and Bosco give chase and capture him, while the firefighters rescue

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.

Faith begs Fred to return home, but he refuses for a reason that infuriates his wife; Bosco turns a cold shoulder to Maritza's attempts to offer her condolences; Carlos is spectacularly unsuccessful in his attempts to hit on Grace; on the day of his son's funeral, Donald Mann exacts his revenge with the help of a dirty cop by planting bombs designed to kill the police officers he holds responsible for the death of his son; after Mann's lieutenants force a man to crash a car carrying a live bomb into the funeral home where Mikey's wake is being held, Grace takes charge and goes out of protocol to save Rose's life, and Dr. Fields later swears to have her job for it; Kim's decision not to enter the funeral home while the bomb is still live stems not from cowardice, but from maternal instincts; when Mann discovers that some of his intended targets survived the bombings, he sends machine-gun wielding minions into the hospital to finish off the job.

After a fierce gun battle and some hand-to-hand combat, Mann's gunmen are finally subdued by the members of the 55 in the E.R., but not before Orland is murdered and Bosco is critically injured; after Kim heroically puts herself in the line of fire to save Holly and a little girl, she realizes that her days as a paramedic are over, and that her future lies in being a wife to Jimmy and a mother to their children; Grace and Dr. Fields patch up their differences and come to an understanding about her out-of-protocol field procedures; Maritza uncovers the traitor in their midst, who leads her to Mann; Faith steps over the line to avenge her partner.

Cruz and Santiago try to track down a gang member who murders witnesses to his murders. Grace finds her mother, who doesn't seem to welcoming.