Adam and Endo rebury three bodies because Five-0 was closing in on the bodies' previous location. Danny meets Joanna's sister Marie at the medical examiner's office. Tani is guest instructor for a firearms-training class that Grover's niece Siobhan is taking at HPB Academy. Siobhan's boyfriend Endo is also at the academy but is secretly Yakuza. McGarrett and Danny search Adam's apartment while Grover and Adam are at Kamekona's because Steve is suspicious of his behavior. Siobhan tells Tani she's suspicious about Endo because she discovered he has two cell phones. She goes to his house and gets caught eavesdropping on him and another Yakuza so they abduct her. Grover is worried because she didn't come home. Tani suggests she spent the night with Endo. Her cell was last switched on in Endo's neighborhood. Adam calls Kenji looking for Endo, his godson, and threatens that their deal is off if Kenji doesn't find her.  Siobhan tries to get through to Endo but Kenji calls just when he was about to untie her. Kenji says he'll take care of Siobhan. HPD picks up Endo. Grover and McGarett grill him. Endo tells them he ended things with Siobhan and she was distraught afterward. Tani finds Endo's second phone in his car vent. Endo tells Adam that Kenji is taking care of things. Adam takes Endo from interrogation. Siobhan escapes from the chair to which she was tied, right into two gunmen. Adam threatens to kill and bury Endo if Kenji doesn't free Siobhan. Kenji caves. Adam is caught on video taking Endo. Adam calls in to tell them he's trading Endo for Siobhan. Steve and Grover arrive as she comes out of the woods. Everyone is suspicious of Adam now. Endo had hacked into HPD's database while at the academy.