A renowned plastic surgeon is killed in Grand Central Station when lye is splashed in his face and on his hands, during the morning rush hour. Mac soon learns that suspects abound since some patients had filed malpractice lawsuits against the doctor. In another case, Stella probes the murder of a blind woman on a Manhattan rooftop. The investigation leads Stella into the world of cuddle parties. Also: Aiden tries to find evidence to send a repeat rapist to prison.