Two years after their escapade in Las Vegas, Stu (Ed Helms), Phil (Bradley Cooper), Doug (Justin Bartha), and Alan (Zach Galifianakis) are traveling to Thailand to celebrate Stu's impending wedding to Lauren (Jamie Chung). Much to Alan's dismay, they are joined by Lauren's younger brother, Teddy (Mason Lee). During Lauren's father's (Nirut Sirijanya) toast, he shows his disapproval of Stu by comparing him to rice porridge. At the end of the night, Stu hesitantly joins Phil, Doug, Alan and Teddy for a beer. Sitting at a campfire and roasting marshmallows, the group toast to Stu and Lauren's future happiness.
The following morning, Phil, Stu and Alan, along with gangster Leslie Chow (Ken Jeong) (whom Alan befriended after Las Vegas) and a chain-smoking capuchin monkey, awaken in a dirty hotel room in Bangkok. Stu has a face tattoo, and Alan's head is completely shaven. However, they cannot find Teddy, only discovering his severed finger. Chow begins recalling the events of the prior night, but his heart stops after snorting a line of cocaine. Panicked, the trio dispose of Chow's body in an ice machine.
