Tooru is staying at his older brother's house while preparing for his entrance exams, but he's secretly captivated by his sister-in-law Remi, and frequently indulges in sexual affairs with her whenever his brother is away. Once again today, as they send her husband off on a business trip, Tooru and Remi exchange suggestive glances, then proceed to let Tooru secretly watch them having sex and tease him with glimpses of her youthful body. This seductive relationship grows even deeper, leading to intense moments that shake Tooru to his core.