Still reeling from the murder of one of their ohana, Steve and Catherine, along with Danny, Junior and some old friends, Harry Langford and Wade Gutches, hunt down the killer. Also, Tani and Grover investigate when a bag of human bones, discovered inside an abandoned storage locker goes missing.

Adam, Junior and Tani travel to the bottom of the Pacific Ocean when a murder takes place in a remote underwater lab, and the killer may still be on board.