The team investigates the murder of Russell Turner, a high school teacher, who's body is found to be completely sliced in half. They suspect the weapon used was a samurai sword which leads them to the underworld of the Japanese mafia and their leader, Takashi Yamada. When Ryan and Natalia go with Tripp to investigate Turner's house, they discover a young Japanese man, wielding a samurai sword and attempting to escape. He tells them that he's Russell's son Kenny. When Horatio looks into the adoption they can't find any record or paperwork that supports his claim. They begin to suspect that he might have been bought off the black market. They match his DNA to Takashi Yamada and discover that Kenny is his son, something that Takashi is already aware of. When Tripp takes Kenny back to get his things, a woman tries to kidnap Kenny. This is Susan Lee who claims she's Kenny's mother. She maintains she has nothing to do with Takashi any longer but befriended Russell Turner long ago. She was pregnant with Takashi's child but didn't want him or her to be entrenched in the mafia world. She convinced Russell to take Kenny while she was in hiding. Before his murder, Russell had called her to tell her that Takashi had found Kenny and Horatio discovers the real reason Takashi looked for so long for his son and it had a lot less to do with reuniting his family and more to do with saving his own life with a liver transplant.