A blowout Las Vegas bachelor party turns into a race against time when three hung-over groomsmen awaken after a night of drunken debauchery to find that the groom has gone missing, and attempt to get him to the alter before his wedding day. In 48 hours, Doug is scheduled to walk down the aisle, effectively ending his reign as a rowdy bachelor. Realizing that this is their last blow out with their best friend, Doug's groomsmen organize a Sin City bachelor bash he'll never forget. The next morning, the groomsmen come to in their Caesar's Palace suite to find a tiger in the bathroom and a six-month-old baby tucked away in the closet. Unfortunately, Doug is nowhere to be found. With no memory of the previous night's transgressions and precious little time to spare, the trio sets out on a hazy attempt to retrace their steps from the previous night, and discover exactly where things went wrong. Will they find Doug in time to get him to the wedding back in Los Angeles, or will his bride experience the sharp sting of disappointment when she walks down the aisle to discover that her future husband is nowhere to be found? Bradley Cooper, Ed Helms, Zach Galifianakis, and Heather Graham star in a rambunctious comedy from Old School director Todd Phillips.