In the lavishly appointed Nakano household, the quintuplets' curiosity piqued by the sight of their eldest sister Miku masturbating, they gather around, wide-eyed and aroused. Ichika, the eldest, leads the exploration, her fingers gliding along her slick pussy as she watches Miku's every move. Nino, the second eldest, can't resist joining in, her hand cupping her breast as she imagines Miku's touch. Itsuki, the third, licks her lips, her eyes locked on Miku's clit, while Yotsuba, the youngest, tentatively touches her own budding breasts, eager to learn the secrets of their shared lust.