After her husband began an affair and left home half a year ago, Miyako tried to stay cheerful, not wanting to worry her son Yusuke. Seeing his mother force a smile despite her pain tore at his heart. He constantly wondered how he could bring happiness back into her life. One night, he discovered Miyako sobbing while masturbating. That moment, Yusuke made a decision. He vowed to take his father's place—not just as a son, but as a man. He gently embraced Miyako and caressed her with tenderness. Though initially hesitant, Miyako gradually let go of her resistance as she recognized the sincerity behind Yusuke's feelings.