Four friends-the groom Doug Billings, his two best friends Phil Wenneck and Stu Price, and his soon-to-be brother-in-law Alan Garner-head to Las Vegas for Doug's bachelor party. After a night of alcohol, gambling, and partying, Alan, Stu, and Phil awake the next morning not remembering the events of the prior night. Unable to find Doug, the groomsmen encounter a variety of problems as they retrace their steps in order to find him.