Starting in 1981, the film follows the life of Satoru Watarai (Hamada) from 12 to 30 years old. After dropping out of Junior High School, Watarai has resolved never to set foot outside his danchi (Japanese apartment complex). As he watches his classmates gradually move away, he begins a daily routine of exercise, martial arts and security patrols which he believes will protect the danchi and preserve its way of life. The film also explores Watarai's struggle to build relationships, make a living and deal with the dilapidation of the complex in the wake of the collapse of Japanese asset price bubble.