An infamous arms dealer, Kurt Renner, is murdered and NCIS:LA goes in search of a black book known to hold the names of weapons dealers they believe the killers were after. An old enemy turned friend from Hetty's espionage days, Branston Cole, is discovered to be the original holder of the infamous black book; he gave it to Renner years ago for safe passage to the West. Hetty, who is protective of Cole, works on her own to try and find Renner's killers knowing Cole's life may be in danger. Callen becomes very concerned with Hetty since he knows she is hiding something from the team and follows her. Meanwhile, Deeks and Kensi go to Renner's house and come upon two men claiming to be NSA Agents. Kensi hears a slight accent and knows they are lying and attacks the men catching them and Deeks by surprise. Her instinct was right and the men were French Intelligence; one of many foreign agents that have descended on L.A to find the black book. Hetty slips away again and meets a man she calls Mattias. It is the man that killed Renner and he tells her what he really wants is Burgess not the book and he knows Hetty is the only one who knows where he is. When Hetty won't divulge his location, Mattias takes her hostage but Calllen and the team were following Hetty and Sam disarms Mattias, saving Hetty. Hetty, knows she has unfinished business with Cole since she was the one who shot him years ago putting him in the nursing home. She returns to his room is shocked to find him shot to death. The investigation into Cole's murder will continue in a future episode.