The year is 1987. Calvin Barr (Sam Elliott) is not a violent man. But he is more than capable of violence if sufficiently provoked. What many don't realize about the thoughtful, elderly bloke regularly seen at the neighborhood tavern is that he's a legendary WW2 veteran who many years ago assassinated Adolf Hitler, an incredible secret that he's frustratingly unable to share. One day, just as he's coming to terms with rounding out his life, Calvin gets a visit from the FBI and the RCMP. They know what he's done, and what he can be capable of. They have a mission for him. After discovering that it harbors a disease capable of eradicating humanity... they need him to take out Bigfoot.