The team investigated the disappearance of a deep sea diver who left a picnic with his girlfriend and her son to respond to a cell phone call instructing him to dive at a specific set of coordinates, where he found three bodies encased in cement. After the man's girlfriend is kidnapped, the team learns that one of the man's former co-workers was injured in an accident and can no longer dive, and has ever since been dealing drugs. Jack finds the girlfriend's son hiding in a closet; after being questioned a few times, he finally tells the team that he overheard the kidnappers talking about where they were taking his mother. Jack, Vivian, and Martin track down the kidnappers and rescue the girlfriend; Jack interrogates one of the kidnappers, who gives him the coordinates of where the diver was being taken. Martin finds the diver and his former coworker on a boat, where the coworker has just forced the diver to dive for a stash of drugs lost at sea-- which resulted in the murders of the three people from the beginning of the episode. Martin subdues the coworker and rescues the diver, bringing to a close the final missing persons case of the series.Meanwhile, Jack reflects on how poor of a parent he has been after Hannah asks Sam to speak to him on her behalf and convince him to let her return to Chicago. Jack and Hannah have a heartfelt talk during which she agrees to stay with him in New York so that they can work on their relationship. Afterwards, Sam and Jack break up-- Jack feels that his daughters will always get in the way of their relationship, and Sam wants to start a family with Brian and Finn.The episode concludes with the team leaving the office to attend Danny and Elena's wedding at City Hall. The camera pans to the white board, and photos of all of the people the team has rescued over the seasons flash quickly across the screen.