Candy and other sweets have been banned, and the kids of the United States aren't going to accept it.

Amidst the swirl of Tokyo's seamy nightlife of designer drugs, casual sex, and American slang, Zhou turns 30. It's a spiritual crisis for this Chinese immigrant who quotes Confucius, this Lothario and con artist who fences stolen goods. He falls for Kyōko, a seemingly shy provincial woman looking for the man who jilted her sister.

Junk Food consists of four intertwining stories. The first and fourth sections show the morning routine of an blind, old Japanese woman, waking up, buying bread and milk, praying at the family altar; however, it is the second segment where the true story begins.

A man becomes obsessed with delusions due to his obsession with a woman he lost, and loses sight of reality. A girl he meets in a rundown entertainment district gently accepts the man's delusions. The only time the two, who seek each other as if to erase the boundary between self and other, feel reality is when they indulge in a dangerous game involving a time bomb... The audiovisual effects, calculated down to the smallest detail, such as the rain and humidity, the deliberate use of red in the color scheme, and the pop song the woman hums, contribute to the continuation of the conceptual story.

The day after being dumped by the boyfriend to whom she was going to give her virginity, Sawako Tsukahara (Kumiko Endo), an office lady in the accounting department of Manpan Trading Co., is dispatched as a helper to General Affairs Section 2. General Affairs Section 2, nicknamed "Shomuni," is the company's cesspool department where underachieving office ladies are gathered. The members of the General Affairs Department are Chinatsu Tsuboi (Reiko Takashima), who is in charge of the department; the femme fatale Kana Miyashita (Michiko Kawai); the self-disciplined Yumiko Maruhashi (Asako Kobayashi); the boastful Kayoko Tokunaga (Mari Hamada); the unremarkable Section Chief Inoue (Masao Komatsu); and the stray cat, Butcha.