Mizuna, an active volleyball player, is invited to test the functionality of new sportswear. She changes into the latest volleyball gear, performing stretches and actual gameplay, during which the recording camera strangely keeps focusing on close-ups of her buttocks and crotch—reasons explained later. Next, she switches to a traditional bloomer to compare functionality. To further evaluate breathability and texture, she is instructed to remove her underwear for inspection. As a male staff member checks the fabric's feel against her skin, Mizuna becomes aroused, seduces him, and engages in intense sex while still wearing the bloomer. Her aggressive, athlete-driven performance during sex is a must-see.