Gloria (Anne Hathaway) is an out-of-work party girl who finds herself in relationship trouble with her sensible boyfriend, Tim (Dan Stevens), and is forced to move back to her tiny hometown to get her life back on track. She reconnects with childhood friend Oscar (Jason Sudeikis), a good-natured bar owner with a coterie of drinking buddies (Tim Blake Nelson and Austin Stowell), and resumes her drinking lifestyle.
Meanwhile, on the other side of the world, a larger-than-life creature begins attacking Seoul, South Korea on a nightly basis, captivating spectators around the world. One night, Gloria is horrified to discover that her every move at a local playground is being mimicked on a catastrophic scale by the rampaging beast. When Gloria's friends get wind of the bizarre phenomenon, a second, more destructive creature emerges, prompting an epic showdown between the two monsters.