Three friends - Doug Billings, Stu Price, and Phil Wenneck head to Las Vegas for a promising epic bachelor party. They take along Alan Garner, Doug's fiancée's unhinged brother - along for the ride. What happens in the next 24 hours they will never forget - or remember. Alan, Stu, and Phil all wake up in a luxury villa at Caesar's Palace - to find Doug, the guest of honor - missing. They also find a chicken, a tiger, a random baby, a missing tooth, and a parking stub. As they put together the pieces of the night before they soon realize that there is more to this story than once thought. And did Stu get married to a stripper? And where is Doug?

Stu is getting married. Along with Doug, Phil, and his soon-to-be brother-in-law Teddy, he regretfully invites Alan to Thailand for the wedding. After a quiet night on the beach with a beer and toasting marshmallows by the camp fire, Stu, Alan and Phil wake up in a seedy apartment in Bangkok. Doug is back at the resort, but Teddy is missing, there's a monkey with a severed finger, Alan's head is shaved, Stu has a tattoo on his face, and they can't remember any of it. The wolf-pack retrace their steps through strip clubs, tattoo parlors and cocaine-dealing monkeys on the streets of Bangkok as they try and find Teddy before the wedding.

In the aftermath of the death of Alan's father, the wolfpack decide to take Alan to get treated for his mental issues. But things start to go wrong on the way to the hospital as the wolfpack is assaulted and Doug is kidnapped. Now they must find Mr. Chow again in order to surrender him to the gangster who kidnapped Doug in order to save him.