The film follows Nishi, a loser who has a crush on his childhood girlfriend. After an encounter with the Japanese mafia, the film follows Nishi as he journeys to heaven and back, and ends up trapped in an even more unlikely place.

The protagonist falls in love with his junior in a college club, and struggles daily to be noticed by her. However, she is naïve and unsophisticated and is completely indifferent to him. This comical love fantasy depicts absurd and interesting daily happenings in the city of Kyoto.

The story takes place in a harbor town where a gloomy middle school student named Kai meets a mermaid named Lu.