A good Samaritan with a police record takes action against a terrorizing subway criminal, forcing the Reagans to weigh the rights and wrongs of vigilantism.

The entire NYPD is mobilized to find the killer of an off-duty police officer murdered during a diamond heist.

When a former U.S. Marine and war hero-turned-homeless man is found murdered, Danny, a former Marine himself, feels a personal connection and is determined to find the killer. Meanwhile, erroneous information about Frank running for mayor is leaked to the press.

Three men attempt to rob a bank and Danny discovers that one of attempted robbers is a former cop. Also, Jamie works with Luisa Sosa, his new partner.

Even while on a case, Danny tries to swing a romantic weekend with Linda. Jamie's undercover assignment involves a crime family.

Danny and Jackie investigate the suspicious murder of a high rolling investor, who had injuries from a fight, but no marks on his hands. Meanwhile, Frank puts Jamie under house arrest, when the Sanfino family put out a hit on "Jimmy Reardon".

Shortly after Frank awards a detective with the Medal of Valor for his undercover work for the NYPD in Malaysia, the detective is taken hostage by a Malaysian drug lord whose brother he helped put in prison. Meanwhile, Henry goes on a ride-along with Jamie and has a different method of getting the job done.

When an officer is accused of using excessive force on a suspect, Frank finds his department under scrutiny from the community and the mayor. Meanwhile, Danny and Baez investigate the murder of a Wall Street securities trader who was deep in debt due to a gambling addition.

Frank and Danny become determined to make sure that an international felon who always manages to walk away from murder charges ends up behind bars. Erin thinks about going into private practice after she looks into college costs for Nicky. Danny clashes with his new boss.

Erin faces off against her ex-husband in court when he represents the person she is attempting to convict of murder. Frank is confronted by a mother who accuses the NYPD of being negligent in solving her son’s murder. Jamie rides with a new partner.

Danny and Baez investigate the murder of a single mother whose ex-husband has a history of violence. Also, Frank deals with the fallout when Mayor Dutton eliminates solitary confinement in prisons, and Jamie’s efforts to save a young woman who overdosed on drugs has unexpected consequences.

When Danny resorts to asking his incarcerated archenemy, Victor Lugo, for help locating a dangerous criminal who escaped from prison, Lugo refuses to assist unless he’s allowed to accompany them on the pursuit. Also, Frank subtly tries to convince Jamie to take the sergeant’s test, and Erin’s plan to go on a date with her ex-husband causes friction between her and Anthony.

When New York City experiences a major blackout, police officers scramble to contain the resulting chaos. Frank uncovers some unpleasant truths about his department. Jamie and Eddie question the line between work and their relationship.

A medium approaches Danny and Baez claiming to know what happened to a woman who was found dead of an apparent suicide. Also, Jamie and Eddie help a woman who bought cheap insulin online that nearly killed her son; Frank goes against the wishes of the archbishop to take down a man he believes is laundering money from a charity; and Erin’s ex-husband asks her for help with an assault and robbery case.

Frank's longtime friend Lenny (Treat Williams) reveals to him that an upcoming exposé will air some of the NYPD's dirty laundry. Also, Erin must decide how to charge a doctor whose experimental treatments led to the death of his terminally ill daughter; Danny and Baez investigate the mysterious overdose of a promising artist; and Jamie follows a lead about a corrupt officer in his precinct.

Frank's esteem for an old friend proves to be a mistake; Jamie asks Erin for help apprehending a perp who shot at him after learning she chose not to send him to prison six months ago; Eddie clashes with her new boss.

Frank takes matters into his own hands to save Gormley's career when complaints against him become public knowledge; Danny and Baez learn to be allies when the transgender community comes under attack.

Jamie faces backlash from fellow officers when he partners with Erin and Anthony to investigate an underground bar the NYPD and FDNY use to hide their criminal indiscretions; Eddie's partner considers leaving the force.

Danny and Baez's attempts to find who assaulted a shop owner are hindered by the community's refusal to cooperate; Erin's suspicions about her boss rise; Gormley, Garrett and Baker are threatened by a new staff member.

Frank, Baker, Garrett and Gormley experience feelings of guilt when Detective Angela Reddick (Ilfenish Hadera), an officer they briefly worked with at 1PP, is shot after Frank reassigned her for not meshing with their team. Also, Eddie, Danny and Baez investigate a man’s murder after Eddie and her partner respond to an altercation between the victim and a neighbor, and Anthony finds himself at a crossroads when he’s offered a promotion that strains his relationship with Erin.

A local celebrity asks Frank to make an exception to the NYPD age limit; an encounter with an old rival leads Erin to look into an alleged wrongful conviction; Jamie is torn over whether to report a sergeant; Danny and Baez look for an abducted kid.

Jamie and Joe search for an undocumented teenage girl who has been sex-trafficked; a woman in witness protection is murdered; Frank calls out the district attorney's office for instituting a new rule that classifies armed robbery as a misdemeanor.

Frank grapples with the personal loss of his best friend and how best to help Tess Ross, the daughter of his best friend, when she lands in jail. Also, Jaime and his nephew, Joe Hill, race against the clock to reunite a trafficking victim with her sister; and Danny and Erin clash when she goes behind Danny's back to use his criminal informant in an investigation.