When five friends accidentally slip into a gnarly, neon-drenched mirror dimension, they find themselves running for their dear lives from the ultimate predators: murderous variations of themselves. Because these evil twins share their exact brains, they easily anticipate every escape route and weapon swing, turning the survival attempt into a brutal, psychological game of chess. To survive the night, the group must resort to chaotic "splatstick" comedy—acting completely against their own natures to trick their own minds and beat themselves to death before they get killed by who they used to be.