In a neglected box in her Tokyo apartment, Ritsuko finds a teenage girl's audio diary on an old cassette. Ritsuko's fiancée Saku spots her in a television report at Takamatsu Airport about an approaching typhoon. He realizes she has gone to their hometown in Shikoku and goes after her. There, at his family home, he discovers a box of audio cassettes. He listens to them while retracting his steps from his school life.