This summer, with record-breaking heat waves that are reported as abnormal weather almost every day, Rin, who has lost her husband and lives a lonely life, is excited when she receives a call from her son that he will be returning home for the first time in several years. It seems that her son, who has been rubbed by the waves of the city, is exhausted...Rin, who can't stand watching her son who is responding to work requests from the company even while returning home, wants to help even a little, so she uses her voluptuous body.