Due to his parents' divorce, Hiromasa ends up staying with his uncle and aunt... His aunt Reiko's caring physical contact makes him feel excited. One day, he hears the sounds of his uncle and aunt's lovemaking coming from their room, and he spends a sleepless night. A few days later, he pretends that nothing happened, but Reiko provokes him with an indecent appearance, and is so excited by his lewd behavior that she starts playing with his erect penis with a smile...