After a girl dies during a high speed chase, a trail of clues leads McGarrett to a Los Angeles prison, where he must act the part of convict Steve Crowley to gain the trust of his cellmate for a break-out, which will help reveal the plans of the crime.

An aging jewel thief steals from rooms at Waikiki hotels, and taunts Five-O by leaving a trail of clues behind.

A geophysics expert, Bernard Brown, is heavily in debt, so he comes up with a plan to cause an explosion in the Hawaii Volcanoes National Park, which will cause lava to pour all down the hillside and into the city of Hilo, unless the Governor comes up with half a million dollars as a ransom.

Eddie Josephs is a paranoid schizophrenic who is carrying out murders based on old Five-O cases. McGarrett must follow his clues and catch him before more people die.

Two conmen use a gang of Five-O lookalikes and doubles to extort money from Honolulu businessmen.

Wo Fat returns to Hawaii in order to have a Chinese diplomat whom he classes as a foolish peace-maker assassinated.

Five-O must find a female courier who witnessed a murder before a hitman can...

McGarrett offers himself as a hostage exchange, but is then put on 'trial' by Honore Vashon.

A clear cut murder case against an island mobster is derailed due to McGarrett.

Ben Tanaka, a well-known ecologist, seems to be behind the kidnapping of a wealthy land developer's wife, but all is not as it seems and a conspiracy gradually reveals itself.