The series concludes with the final showdown between McGarrett and Wo Fat. Three scientists have gone missing. They have one thing in common: they all attended a symposium that discussed a possible space-based, laser defense system. McGarrett impersonates a fourth scientist, Dr. Elton Raintree, who attended the same gathering and is soon abducted. Wo Fat is behind it all and wants the scientists to complete their work and produce such a device.