Danny investigates when a doorman at a nightclub is murdered; Frank makes a decision about a former partner's future.

Just before Danny is to give witness testimony at a Peruvian drug lord's murder trial, Linda is kidnapped. This drug lord has a history of intimidating witnesses.

Erin has to re-open a 18yr old rape case in which Frank was the arresting officer. Danny and Jackie have to deal with the murder of three teenagers for which there appears to be no motive.

Danny and Jackie investigate a murder scene at a diner, where a witness claims a uniformed officer fled the scene after shots were fired.

Danny causes waves in the department when he investigates a closed case, the suicide of a firefighter, at the insistence of the man’s 12-year-old son. Meanwhile, Jamie saves a baby from a burning building but worries it will jeopardize his undercover work when he is billed a hero in the press.

Erin and Danny investigate a cold case of a girl who was attacked by her rich and powerful boyfriend, who was never convicted. Meanwhile, Jamie’s friend brings a lawsuit against Danny’s friend after an injury at a pick-up basketball game.

A woman dies after undergoing a secret plastic surgery, so Danny and Baez try to figure out what happened. Elsewhere, Frank asks Jamie to solve a cold case; and Erin explores the world of speed dating.

Frank is put in a difficult position when Danny is charged with using excessive force. Jamie brings homeless man to the hospital.

Frank is left with minimal information to find a missing boy when a conflicted priest who could help won't break the seal of confession. Also, Danny and Baez investigate the death of a prominent New York City socialite with a secret life, and Jamie and Eddie attend a wedding together.

When a student is shot by a rival gang member in his high school courtyard, Danny and Baez try to get a grasp on the situation to prevent a reoccurrence, but the principal recklessly takes matters into his own hands. Also, Erin tries to help a friend who is mixed up in an illegal gambling ring; and Gov. Mendez tries to frame Frank after one of his top legislative aides is shot by an NYPD officer

Jamie clashes with Eddie and her new partner when they fail to intervene in a dispute at a convenience store. Danny and Baez investigate the death of a college freshman at a fraternity party. A sergeant accuses the department of reverse racism.

Jamie is under investigation after his police vest is found on a perp. Frank debates whether to aid and protect an old friend whose home was invaded. Danny and Baez investigate the suspicious circumstances surrounding the death of a hotel employee believed to be a suicide. Erin asks Anthony to make a deal with a man who knows secrets about the current D.A.

Shockwaves ripple through the Reagan family when Danny discovers that their newest family member, Joe Hill (Will Hochman), is working undercover for the ATF to bring down a gunrunning organization.

The Reagans band together to prevent Joe Hill from being killed in the line of duty like his father when they fear Joe’s cover has been blown within the gunrunning outfit he’s helping the ATF bring down.

Danny pursues a con artist pretending to be the legendary singer Jimmy Buffett; Frank investigates an impressive police captain who is using her badge to get free wares from local stores.

Frank contends with a potentially dirty cop within his ranks; Eddie and Badillo track down the culprits behind the theft of valuable, rare works from a celebrated bookstore; Erin snoops into the background of a new woman in Anthony's life.

Eddie and Jamie deal with a domestic violence case associated with an investigation lead by Danny and Baez; Frank and his friend go on a mission to avail themselves to an unfiltered look at the city; Erin is presented with a surprising offer.

Frank announces he will not endorse Erin's run for district attorney; Danny and Baez investigate a bloody crime scene at a hotel; Jamie begins a new job as a field intelligence sergeant that requires him to keep secrets from his family.

Frank launches an investigation after the Reagan family is harassed; Danny and Baez form an unlikely partnership with an informant in order to prevent a murder; Eddie lands in hot water after she defies a direct order.

Danny and Baez team up with Danny's old partner to find a copycat killer emulating a criminal's murders from a previous case; Frank and Mayor Chase battle over how best to handle the city's rising homeless population.