Yoshi, on a bug-catching trip, discovers an unfamiliar girl named Sachi trapped in a mountain phone booth, distressed by a broken phone. Unable to leave her, he enters, only to have his net jam the door, locking them both inside. As the summer heat becomes unbearable, they are forced to shed layers of clothing, leading to flustered awareness and accidental physical contact. When bugs escape from Yoshi's cage, Sachi panics and clings to him, making him acutely conscious of her proximity. Trapped together in the confined space, their secret, sweaty, and tense summer memory begins.