 A series of bomb threats against a state senator culminate in a car-bomb blast that kills his secretary. But Five-O realizes that the only tie-in to the threats and explosions is the senator himself. Five-O calls in a psychologist who determines that the senator has multiple-personality disorder -- one side of him is threatening the other, when the senator, as a young boy, fatally shot his own father in a rage, the guilt over the incident gradually caused the senator to lose his mind, making him two people, one normal and one consumed with destroying the other. The "bad" senator rigs up another bomb for the "good" senator to pick up and carry in an outdoor elevator, figuring the blast will annihilate him and much of the hotel where he s staying. McGarrett must get to the senator and get the bomb away from him before the senator -- and McGarrett himself -- go out in a blaze of glory.