In the Season 7 finale, Danny intercepts a shipment heading to a drug cartel in Mexico, so this makes him a target of revenge. Meanwhile, Jamie searches for a serial killer preying on the elderly; and Mayor Poole confides in Frank his plans to retire.
Danny and Baez team up with Russian operatives to search for a dangerous man who entered the U.S. on a diplomatic visa. Meanwhile, Frank gets involved in with a case concerning the archbishop; and Erin needs to figure out who tampered with her evidence.
Erin’s help is sought by a witness in one of her old cases, and she obliges because the man wants to shut down a drug operation. Meanwhile, Danny and Baez suspect that a teen’s suicide was really homicide; and Frank investigates potential misconduct in the mayor’s office.
Erin opposes her ex-husband in court when he represents someone she’s trying to convict of murder. Meanwhile, Danny and Baez investigate a husband whose wife was murdered; Frank deals with a bereaved mother; and Jamie rides with a new partner.
Danny investigates the disappearance of a former cop who planned to make amends with a woman she wrongfully convicted years ago. Meanwhile, Frank must deal with a peer who refuses to retire, even though he’s hit a mandatory age limit.
An EMT doesn’t respond to his wife’s distress call when she has an allergic reaction to medication, so Jamie and Eddie suspect foul play. Meanwhile, Erin realizes she may have convicted an innocent man; and an exposé on Garrett leads to a PR crisis for Frank.
Linda’s brother asks for help from Danny after he lands in trouble with the mob. Meanwhile, a lawyer whose client was wrongfully arrested wants police officers’ disciplinary records to be made public; and Nicky accompanies Jamie on a ride-along.
A man is murdered 10 years after he killed a mother and son while driving drunk, and the investigation leaves Danny and Baez facing a dilemma. Elsewhere, Anthony is put in a difficult position when Erin asks him to wear a wire when meeting an old friend who has mob connections.
A parole officer’s romance with an ex-con leads to a possible cover-up in a gang leader’s shooting. As Danny and Baez investigate the murder, Frank tries to halt further violence by talking to a rival gang leader who once killed a police chief.
A child-abuse case gets complicated for Danny and Baez because of an individual’s diplomatic immunity, so Frank gets involved, even though he doesn’t have jurisdiction. Elsewhere, Eddie and Jamie deal with a robbery while they’re off duty.