Stu is preparing for his wedding in Thailand and invites his friends Phil, Doug, and Alan to join him. Reluctantly, he also invites Teddy, Lauren’s younger brother. The group, determined to avoid the chaos of their previous adventure, has a quiet pre-wedding brunch at the resort. Later, they gather around a small campfire on the beach along with Teddy, toasting marshmallows and beers. The next morning, Stu, Phil, and Alan awaken in a seedy Bangkok hotel room with no memory of the previous night. Stu discovers a facial tattoo, Alan's hair is shaved, and there is a severed finger that appears to belong to Teddy. Panicked and confused, they realize Teddy is missing and must retrace their steps to find him before the wedding.

Their quest to piece together the events of the night leads them through the chaotic streets of Bangkok, involving encounters with tattoo parlors, high-stakes gambling, and dangerous criminals. They discover they have been involved in drug deals, theft, and a monk with unique knowledge of their night’s activities. As they navigate this labyrinth of trouble, they rely on their fractured memories, each other's support, and occasional risky decisions to solve the mystery. Eventually, they learn shocking truths about their night, righting their wrongs in the nick of time to not derail the approaching wedding.