Teacher Haruka comes to stay at her nephew Shota-kun's house in Tokyo while attending a training seminar. Innocent Shota-kun pretends to play innocent games with her, but starts a series of naughty pranks—playing doctor and using a stethoscope to fondle Haruka’s large H-cup breasts. One by one, his erotic teasing escalates. Gradually aroused by his provocative actions, Haruka gives in to temptation. Her huge breasts bouncing wildly, she grinds her hips vigorously, passionately engaging in extremely lewd sex with her nephew Shota-kun. This story captures the deepening, intimate relationship between them, where warmth and lust intertwine.