Having just moved into his new apartment, Tomoki finds himself spending his nights listening to the moans coming from the neighboring unit. The source of the sounds is a married woman named Yuka. This discovery deeply unsettles Tomoki. Unable to resist the sounds echoing from next door once again, he secretly begins to spy. There, he sees Yuka writhing in ecstasy as she pleasures herself. Mesmerized, Tomoki continues watching until suddenly, Yuka's eyes meet his. Panicked, he flees back to his room. The next day, Yuka casually visits Tomoki's apartment, pretending nothing happened. Yet something about her demeanor feels suspicious, as if she's hiding a deeper intention.