Akira Tachibana is a 17-year-old high school student. She was once a promising athlete, but an injury has prevented her from taking part in track and field. One day, Akira Tachibana goes to a family restaurant and the manager talks to her in a tender voice. This makes Akira Tachibana begin working part-time at the restaurant. The manager is 45-year-old Masami Kondo and he is divorced with a child. Akira Tachibana falls in love with him.

Ishimori Uka is very shy and has a hard time making friends. When she was a middle school student, students made fun of her by calling her "stone". Around that time, she met Miura Kai with lemon color hair. Because of him, she entered the same high school. Uka now wants to overcome her shyness and have friends. Kai is a popular student at the school, but he doesn't talk much or seem interested in others. He doesn't know why, but he becomes concerned with Uka. Uka has admired Kai, and she now has feelings for him. Kai has a secret, which no one knows.

The director, twenty-three-year-old Iwabuchi Hiroki, is a permanent part-timer who on weekdays does menial work at a factory for 1,250 yen an hour, and on weekends takes on casual temporary work in Tokyo, a city he is fascinated with. He joins a demonstration demanding rights for permanent part-timers, and is featured on TV as "a poor, unhappy temporary worker." Despite having made his own choice to live as a permanent part-timer, he says that "the days feel like drowning in shallow water." But during the diary-like documentation of his life, something changes...