The shooting at Mann's apartment is investigated, and all involved stood down for three days. Upon their return Faith gets served, and receives a promotion. Cruz has a new boss and gets an anonymous tip about a rat in the house. Ty meets up with some old foes and bungles their arrests. Munroe has a secret.
Ty gets a rookie partner with family connections to IAB. Carlos gets cursed by a patient's psychic. A Chinese bride is shot at her wedding. Faith asks Fred if their kids can attend her promotion ceremony at One Police Plaza. Monroe finds a way to connect with Yokas.
Faith starts duty as a detective, with Jelly filling her in on the details. Sully and Monroe attend a domestic and discover a suicide in the upstairs apartment. Faith takes an interest in the guy's background and finds he may have killed a woman. Sasha and Ty make up, then find a dead body in the garbage by the squad's house.
Miller recognizes the M.O. of the body found dumped by the squad house and works on the case with Yokas. Finney and Buono get talking. Carlos denies there is anything happening with him and Levine. Munroe is working to a deadline. Carlos and Buono are ambushed. The murderer hands himself in - after he has set up another girl to die slowly.
Faith and Fred go to court to fight for custody of the kids. IAB interrupt, taking Faith away with them. A cute new firefighter arrives. Cruz is denied bail and sent to Rykers on remand. Under full immunity, Faith confesses the truth. A potential suicide causes problems. Sully tells Ty something about the history between himself, Ty's father, and C.T. Finney. Bosco wakes up.
Munroe looks into the past. A missing councilman is found by Carlos and Grace in a bloody and dazed state. Fred's girlfriend reports Charlie missing to Faith. Finney Sr gets wind of Ty's investigations into his father's death.
Faith and Jelly investigate the murder of a Muslim school girl and Faith suspects an honor killing. Ty continues to ask questions about his father. Munroe's secret is revealed. Brendan is a hero and gets a second chance with Grace. Emily makes a choice.
Ty reveals Munroe's secret to the squad. When Munroe and Finney Jr are attacked, there is little response to their 10-13 call. Faith investigates the murder of a retired IAB detective. The fire crew have a has-been actor on a ride-along to study for a part.
Holly says "the L word" to Carlos and he doesn't know how to respond. Bosco is looking forward to his release from hospital. A simple notification turns out to be anything but for Cruz when there might be a terrorist with a dirty bomb. Brendan is worried for his father when CT says he loves him.
The police squad house is evacuated to the fire house across the road. Carlos says the wrong thing to Holly and she leaves. Bosco is discharged from hospital. Grace comforts Brendan. Cruz makes a breakthrough on the dirty bomb case. The tests for radiation poisoning show up something that she already knows.
Sully responds to a robbery, and an exchange of gunfire, at a friends jewellry store. Carlos is exposed to a mysterious illness. Maddox is shot dead in the precinct when Cruz and Santiago are taking him to central booking. Bosco is cleared to return to duty. This episode is Part 1 of a crossover with Medical Investigation that concludes on "Half Life". Neal McDonough and Kelli Williams guest star as their respective Medical Investigation characters - Stephen Connor and Natalie Durant.
Bosco teams with Munroe for the day and they deal with a woman demanding her missing welfare check. Ty and Brendan get into a stake-out and discover a prostitute working out of a hot dog truck. Cruz finds she is not alone.
Carlos buys a ring. A young man's parents are shot and Finney and Davis are left for dead in their upturned car. Emily is invited to the vampire club and rejects them. Grace is disturbed by her feelings towards Finney when he is injured.
Emily inadvertently lets the vampires into the apartment. Cruz and Santiago are targets of a drive-by shooter. Yokas handles a hostage crisis at a TV station. Bosco proves his shooting ability. Carlos has trouble saying what he wants to say to Holly, and gets some sage advice from Stu. A grenade is thrown into the police house.
The police house is under grenade and gun attack by Marcel Hollis's crew, and he escapes from custody. The building is evacuated, with Munroe and Cruz inadvertently left behind upstairs, trapped by rubble and fire.