Hiroshi, the only son whose father has remarried to a woman 20 years younger and lives under one roof with his mother-in-law Azumi. For Hiroshi, who is unemployed and has never met a woman, Azumi's crisp skin, who is only four years old, is too stimulating. Azumi always plays with Hiroshi at the last minute, whether she knows Hiroshi's pure feelings or not. One day, when they thought their relationship would continue, something happened that changed their relationship.
