Stella and Danny are heading into the world of cuddle parties: non-sexual events were adults learn to touch and hug each other. Meanwhile, Mac, Hawkes, and Flack investigate the death of a hated plastic surgeon found covered with lye with thousands of eyewitnesses during rush hour at Grand Central Station. While Mac and Stella assist Aiden in a rape case, after she breaks an evidence seal, Mac must come to terms with Aiden's action and work up the nerve to fire her.