Josh Hartnett joins the post-apocalyptic fun! Josh Hartnett has joined the cast of the upcoming post-apocalyptic adventure Gunslinger. Described by Variety as a “revenge-driven tale”, the film focuses two brothers as they attempt to take out the gang who killed their parents. “This story takes a unique and startling look at what might happen when the lawlessness of the Old West returns,” said producer Mark Williams. “But with better weapons.” Hartnett will reportedly play the lead in character in the filmed helmed by Chris Nahon.