Alan（扎克·加利凡纳基斯 Zach Galifianakis 饰）已经42岁了，却还和老爸老妈住在一块，有一天他的老爸“终于”被他气死了。Alan的几个死党Phil（布莱德利·库珀 Bradley Cooper 饰）、Stu（艾德·赫尔姆斯 Ed Helms 饰）和Doug（贾斯汀·巴萨 Justin Bartha 饰）决定带着Alan去亚利桑那的一个地方给他心理治疗。四个人在路上意外被一个叫Marshall的人给劫持了。原来这一切都是Leslie Chow（郑肯 Ken Jeong 饰）惹的祸。Chow从曼谷的监狱里逃出，并且劫走了Marshall的价值四千两百万的黄金中的一半。Marshall为了找出Chow，留下了Doug，让其余三人去把Chow带回来。Alan一直和Chow有联系，三人很快和Chow见了面，为了救回Doug，Chow决定带他们三人回原来自己的家中，取回那两千一百万黄金。眼看四人历经艰辛终于把黄金拿到了手，Chow却把他们三人锁在地下室，自己一个人带着黄金扬长而去。他们是否能救回Doug，这四个人又将经历怎样一段冒险旅程？

The Hangover crew heads to Thailand for Stu's wedding. After the disaster of a bachelor party in Las Vegas last year, Stu is playing it safe with a mellow pre-wedding brunch. However, nothing goes as planned and Bangkok is the perfect setting for another adventure with the rowdy group.

When three friends finally come to after a raucous night of bachelor-party revelry, they find a baby in the closet and a tiger in the bathroom. But they can't seem to locate their best friend, Doug – who's supposed to be tying the knot. Launching a frantic search for Doug, the trio perseveres through a nasty hangover to try to make it to the church on time.