Frank and Joe 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 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 childhood friend and a former criminal Mickey Patrick, 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.
The return of Rachel Witten, Eddie's former partner turned social worker tests her loyalties and conflicts Frank when Rachel brings an accusation of excessive force against an officer.
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.
Frank clashes with Mayor Chase when an influx of immigrants arrives in the city. Danny and Baez investigate a case of grand larceny tied to feuding crime families.
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.