Every summer for the 12 years since their dad died, brothers Adam, Tim, and Kevin have made the pilgrimage to their family cabin for a weekend of drinking, lighting stuff on fire, and memorializing the best man who ever lived, a tradition dubbed Man Camp. But when they arrive to find their mom messing around with some new guy named Alan who's nothing like their dad was, the balance of their family dynamic is thrown into a tailspin. Upon learning of their plans to marry, the brothers invite Alan to stay for the weekend for some bonding time, all the while cooking up a sinister plan to rid him from the family for good. Through a wild gauntlet of pranks, tests of manhood, and emotional manipulation, they'll have to decide whether or not they're ready to move on from the way things used to be.