While her sister was away on a trip with her husband, Minami Umeda was asked to look after her nephew, Tatsuya. Reuniting after a long time, the two reminisced fondly and shared warm, heartfelt moments. However, Tatsuya had secretly been in love with Minami for years. Overcome by his pent-up emotions, his affection spiraled out of control, and he gave in to his desires, reaching out to her.