On a scorching summer day Yuzu comes to older brother’s house as a guest. Air conditioner is broken. Sister-in-law Unpai can’t stand the heat and takes off clothes leaving only a bikini. As the heat becomes unbearable Yuzu drinks more and more unable to resist sister-in-law’s temptation. And when the bikini-wearing sister-in-law walks toward him… this is the story of how he and the exposed-swimsuit sexy firm-ass sister-in-law put on a sweat-soaked passionate encounter…