A high school girl wakes up each day with no memory of the day before. When she agrees to date a shy classmate, Toru, he begins to fall for her—despite her rule against falling in love.

College sweethearts Riku and Minami marry. He becomes a novelist while her singing dreams fade. After a fight, she vanishes. Suddenly, he's just an editor, and a singer named Minami Maezono exists-but he's never met her.