Sgt. Sidney Gormley is promoted to Lieutenant. At the ceremony, Frank recognizes the father of a detective as a fugitive Donald DeCarlo and has him arrested. He was the man Henry said he saw shoot another officer back in 1976 but when Erin interviews Henry, his memories of the event aren't clear. Erin considers a plea deal but Frank gets DeCarlo's son, now an NYPD Detective to wear a wire in which his father confesses to the crime. Henry is there when DeCarlo is arrested.
Danny and Baez are caught in the middle of a shooting on a busy street where Curtis, who was shot in the groin in his apartment then ran three blocks while being chased by his shooter before he died. Turns out Curtis was involved in the erotic film industry with a young woman named Josie Philips who later committed suicide. When two more people involved with the industry are murdered, Danny and Baez catch Josie's father in the act.
But the M.E. determines that at least one of the victims was killed by a woman and they catch Josie's mother who is trying to kill another person involved with her daughter's former profession.
Jamie and Eddie come up on the scene of a crowd trying to kill a man who hit a young girl with his car. The girl will be OK but the man is arrested for a DUI. One witness tells Eddie that someone else was driving the car and got out and Mr. Santiago got into the driver's seat. The detective on the case is uninterested as she already got Mr. Santiago's confession. Jamie and Eddie figure out that Mr. Santiago's son was the driver. The mother makes her son confess, saying that his college scholarship isn't worth doing the wrong thing.