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.

Danny and Baez investigate after a vicious attack leaves their mutual friend, Maggie Gibson, hospitalized; Frank and the team debate the appropriate memorial protocol for a former police commissioner with a questionable professional legacy.

Danny and Baez investigate a series of violent robberies targeting luxury timepieces; Erin is conflicted about criminally charging a potentially innocent man; Frank is forced to reopen a case in which the officer involved was acquitted.

Danny and Jamie clash over a gang-related shooting; Erin and Anthony search for answers when a lawyer in their office jeopardizes a case involving Erin's nephew; Frank grows concerned when he's not invited to speak at a policing forum.

Erin and Anthony clash when Anthony's daughter is the sole eyewitness to a fatal shooting; Frank wants to punish an off-duty cop for his inaction during an armed robbery; Danny and Baez investigate a violent mugging.

Danny crosses paths with a criminal from a previous case when he investigates a gang attack with a shocking motive; Frank and Mayor Chase butt heads over an off-duty cop who goes too far making a political statement.

Frank and his grandson, Joe Hill, contend with a grievous insult to the memory of Joe's father; Erin and Henry work together to bust a scammer targeting the elderly; Eddie's captain takes suspicious interest in her efforts to locate a stolen puppy.

Jamie and his new intel team officer infiltrate a high-tech car smuggling ring; Frank faces off against the city's transit chief over a program that is causing officer injuries on the job; Eddie asks Danny to help her bust a cop impersonator.

Danny and Baez’s investigation into the death of a chess hustler is complicated by interference from the victim’s son; Jamie tries to make amends with a man he regrets putting away as a young officer.

Danny reunites with Mickey Patrick, his childhood friend and a former criminal, who comes to him for help finding his missing fiancee; Anthony surprises Erin with one last stakeout before her run for district attorney.

Danny and Baez race against the clock to catch a serial killer targeting young women; Erin and Eddie clash when Eddie intervenes in a murder case and Erin's personal life; Frank must decide how to discipline his grandson.

Eddie's former partner returns and brings an accusation of excessive force against an officer; Danny and Baez clash with a troubled foster child at the center of their latest investigation; Erin must make a tough decision about her campaign.

Danny partners with Texas Ranger Waylon Gates to deliver an infamous drug cartel boss to arraignment, but the mission becomes complicated when the criminal threatens to harm the Reagans; Erin takes on a highly contentious assault case.

Jamie learns that Eddie’s close friend Tracey may be using the restaurant she owns as a drug front; Erin is accused of causing the suicide of a former colleague; Danny and Baez are faced with various descriptions of the same suspect.

Frank clashes with the team when one of the members becomes the focus of a departmental investigation; Jamie and Danny team up to investigate a series of carjackings involving one of Danny's criminal informants.

Danny and Baez investigate a case of grand larceny tied to feuding crime families; Frank clashes with Mayor Chase when an influx of immigrants arrive in the city; Erin questions whether her district attorney campaign is compromising her day job.

Jamie partners with the FDNY to find the arsonist responsible for a massive fire at an NYPD evidence storage facility; Eddie asks Frank to put her on modified duty following her divisive arrest of an anti-cop protestor at a rally.

Frank worries his longtime friend is hiding his true reason for returning to the city; Baez and her daughter are targeted by a criminal Baez once put away; Anthony is sucked into the inner workings of an underground crime ring.

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.