Dr. Benton Quest's perennial nemesis, Dr. Zin, wants to get his slimy hands on a powerful tranquilizing pill that can paralyze entire cities. Both Quest and Zin are given a run for their money by the estimable Jezebel Jade, a fortune-hunting temptress who is sweet on Jonny Quest's bodyguard, Race Bannon. The episode's title refers to the fact that Race Bannon is briefly replaced by a sinister lookalike named Korchek. Reportedly the first Jonny Quest episode produced, though not the first one to be shown, "Double Danger" originally aired on November 13, 1964. ~ Hal Erickson, Rovi