MacElwaine becomes embroiled in a hostage situation on the last day before his retirement; promoted Santoro learns his wife is pregnant again.
Johnson is critically wounded during an undercover operation; Jimmy Doyle covers for a negligent officer.
Lowery and Valentine's relationship heats up; extremists threaten the subway system; Santoro's new assistant does everything four times.
Lowery and Valentine celebrate a birthday; undercover Kersey accidentally kills a drug kingpin; Rousakoff investigates a dognapping.
An abused woman refuses to press charges, then her husband is murdered; Lowery's former fiancee turns up dead.
Donovan's father visits; Valentine tries to help a prostitute; Roussakoff unintentionally disrupts a funeral.
People start avoiding Donovan after he confesses to being a field associate for Internal Affairs; a landlord has a tenant killed over an eviction notice.
Denton frames Santoro for extortion; Donovan risks exposure by going to Jonas for help; tensions mount between Johnson and Lowery.
A woman attempts suicide; gang warfare breaks out in an emergency room; Valentine asks Johnson to tail a beautiful Russian.
A veteran cop from another precinct finds that the person running a local rehab is responsible for stealing from the donation tables.
Jonas seeks Donovan's help when an old friend kills a man suspected of sexually harassing his teenage daughter.
Hegan testifies about his part in a gay-bashing; Fiano stops a burglary at a gay bar; a new lab man questions Santoro's alliance with Fiano.
A mob leader suspects Terry and feeds him false information about the gang's planned bank robbery; Kevin comes back to work in a wheelchair.
District Attorney Woody McKenzie's ex-wife turns up dead; undercover encounter; Santoro and Jonas make the station handicap accessible.
Santoro offers a precinct job to paralyzed Officer Patrick; six people are found murdered in an apartment complex.
Two officers are accused of beating a gay couple; Terry Doyle goes under cover; Jonas is promoted to captain of the 74th precinct.
A religious leader pressures Officer Johnson; Santoro goes under cover to expose a fence; abusive husband.
Exhibitionists dressed as clowns are arrested; Lowery helps a man retrieve a stolen stamp collection; Donovan and Kersey spend time together.
Thanks to Kersey, a grand jury clears Lowery of all charges in the death of Deshawn Hopkins; the feud between the Westrope and O'Donnell families turns deadly.
A case of mistaken identity has the Hasidic community up in arms; Lowery is accused of brutality; a domestic dispute involves neighbors; guest Theodore Bikel.
Tensions in the community escalate when word gets out that a suspect who died while in police custody was allegedly beaten.
Borough police officers tackle personal and professional challenges; with Jon Tenney, Michael DeLuise, James B. Sikking.