A murder attempt on a Pearl Harbor veteran leads Five-0 to use decades old evidence to investigate a deadly crime committed in an internment camp on Oahu during WWII.
After one of Governor Jameson's assistants is killed, McGarrett discovers that the governor may have been working with Wo Fat and may have been the target of his father's investigation.
McGarrett escapes from prison and sets out for revenge on Wo Fat, with the help of his now-disbanded Five-0 team and the man who trained him in the Navy.
Five-0 needs the help of an imprisoned dirty cop to track down a suspect who killed Captain Fryer and set off a bomb in the HPD. Meanwhile, Joe White returns and promises to reveal Shelbourne's identity to McGarrett.
Wo Fat kidnaps McGarrett to get answers about his father. He drugs McGarrett during his interrogation, which causes him to have hallucinations that his father is still alive.
In order to stop a meth epidemic on the Island, McGarrett and Danny go undercover as pilots, but when McGarrett is seriously wounded, Danny is forced to break their cover in order to save his partner's life.
While Five-0 investigates the death of a muckraking reporter, Jenna returns to ask McGarrett for help finding her fiancé in North Korea--which is actually part of Wo Fat's revenge plot--and Joe White leads the mission to bring them home.
Five-0 discovers a terrorist cell on the island; Danny has a flashback to one of the most eventful days of his time as a Newark police officer in 2001.
Five-0 captures a seriously wounded Gabriel Waincroft and prepare to bring him in, but Michelle Shioma wants him for herself to avenge the death of her father, and her men will stop at nothing to get him for themselves.
