The investigations of Hawaii Five-0, an elite branch of the Hawaii State Police answerable only to the governor and headed by stalwart Steve McGarrett.
Five-O must close the heroin smuggling operation to exonerate the Governor and catch the figures behind the scheme.
A cowboy fears the loss of his land to a crooked estate agent and accidentally kills him by hitting him. McGarrett and his team must track the cowboy into the mountains and persuade him to give himself up.
Jessica Humboldt, an astrologer and friend of Agnes DuBois, comes to McGarrett with news that a forthcoming match will be disastrous for a boxer. McGarrett must overcome his suspicions and crack the case.