A group of high society men set out to see that justice is done - the catch being that it is justice on their terms only...

Tony Alika and Guido Marioni, killer of Kimo's family, together hatch a plot to frame and embarrass the Five-O team by making them look stupid or corrupt.

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.