Two years after the disastrous events in Las Vegas, it is now Stu's (Ed Helms) turn to walk down the aisle. Since his bride is from Thailand, Stu decides to hold the wedding there. Desperately hoping to avoid the mayhem of Doug's (Justin Bartha) bachelor party, Stu chooses what he thinks will be a safe option: an alcohol-free, prewedding brunch. But this being Thailand, and with Phil (Bradley Cooper) and Alan (Zach Galifianakis) again in attendance, anything can happen.