Hirose Natsumi works at a fairly good company and generally lives a fulfilling life, but she still feels a sense of dissatisfaction. Then, just before turning 30, she is dumped by her longtime boyfriend, and a stranger appears at her house. At her aunt's request, Natsumi moves in with a younger man named Hisahara Yu, who aspires to be a pianist... The story depicts how, as she lives with Yu, Natsumi begins to remember a dream she had forgotten.