After the death of his father, college student Takahiro struggles with his relationship with his stepmother, Mai. Though still young, he is unable to heal his emotional wounds. Concerned for him, Mai wishes for him to call her "Mom" and gradually works to close the emotional gap between them. Meanwhile, Takahiro has a devoted older girlfriend named Eriko, with whom he shares a deep bond that occupies his heart. However, in a shocking twist, it is revealed that Eriko is actually Takahiro's real mother. Overcome with jealousy and anxiety toward Eriko, Mai—despite her own deep affection—kidnaps her. Soon after, Takahiro's relationship with Eriko takes an unexpected and intense turn.