Members of an American scientific research outpost in Antarctica find themselves battling a parasitic alien organism capable of perfectly imitating its victims. They soon discover that this task will be harder than they thought, as they don't know which members of the team have already been assimilated and their paranoia threatens to tear them apart.
By the turn of the 20th century, Butch Cassidy, the Sundance Kid, Billy the Kid and virtually all of the West's legendary outlaws are either dead or in jail pending execution. Well, all, except train robber and escape artist extraordinaire, Harry Tracy. As the last survivor of the Wild Bunch, Tracy pulls off a series of profitable robberies before making his way west to Portland, Oregon, in search of Catherine Tuttle -- a judge's daughter who has captured his heart. But on the way, Tracy is betrayed, arrested, and imprisoned. However, no jail can hold him for long and after making his escape, Tracy becomes the target of the largest manhunt in the history of North America.