Mother Hisayo has raised her son Kazumasa on her own since he was a child. After losing her husband, she always cherished and deeply loved him, pouring all her affection into raising him right. As a result, Kazumasa grew up honest and upright, never straying down the wrong path. However, Hisayo's maternal love became overwhelming, and she grew anxious about Kazumasa developing feelings for other women. Holding onto this worry, Hisayo returned home completely drunk after a drinking party. When she saw Kazumasa tenderly caring for her, she could no longer suppress the forbidden emotions welling up inside her.