Reason shattered by the plump temptation of Mio Ishikawa. Mio, my wife's younger sister, stayed at my house for just two days. Relaxing carelessly in her panties, my eyes were irresistibly drawn to her prominent plumpness... 'No way... she's my wife's sister...' No matter how many times I looked away, the lewd shape visible even through the fabric, the irresistibly plump mound that I couldn't help but touch, my reason collapsed! 'I don't care if we get divorced...! I'm going to do it...! I'm going to do it!' Day and night, morning, non-stop action! Whether in the bath, with my wife nearby, or even while sleeping...! The piston of lust doesn't stop for Mio's plump temptation! The angles that make you excited just by looking are thoroughly satisfying! Any man would want to suck on Mio's beautiful plumpness, a situation to fully enjoy! It's nothing less than a national treasure. After actually watching it, there's no doubt that reason would collapse under such temptation from a sister-in-law. The scenes where you can't resist the temptation and end up inserting are unbearably exciting. And the development into an affair... such a plot is full of a sense of immorality, guaranteeing excitement. Mio's smiling face in the subjective parts was really cute. There's no other work as temptingly provocative as this.