Five-0 must help Duke after he is forced to steal crucial evidence from the police locker in exchange for his kidnapped granddaughter. Also, Jerry goes undercover at a mental health facility in order to solve a murder.

McGarrett joins Junior and his SEAL Team on a high risk covert mission to capture an elusive target who is holding his mentor, Joe White, hostage. Also, Gerard Hirsch and Kamekona help Grover and Tani on a murder case involving masterpieces stolen by the Nazis during WWII and Tani makes a shocking discovery.