Evan (Ben Stiller Ben Stiller) is a store manager in town who is also very active in community affairs. However, the store security guard was accidentally murdered, but the local police had no intention to pursue it. Evan's life was disrupted, and he was determined to find the killer himself. Evan sets his sights on the neighborhood and forms a neighborhood defense team with Bob (Vince Vaughn Vince Vaughn), Franklin (Jonah Hill Jonah Hill) and Jarmax (Richard Ioad Richard Ayoade) who are also frustrated in life, patrolling the town every day and occasionally indulging for this reason. On a driving patrol, they accidentally found a strange metal ball. at the same time, there were several mysterious deaths in the town. The joint defense team subdued it when it was attacked by an alien creature and learned that the aliens had invaded the town. and by stealing human skins to pretend to be adults, to carry out the offensive. The joint defense team knew that the action was imminent but looked at it in vain, because anyone in the town could be an alien, but what is even more frightening is that the ultimate goal of the alien.