Yumi Kazama is left to look after her nephew, Yoshihiko, while her husband is away on a business trip. Growing tired of Yoshihiko's reckless and arrogant behavior, Yumi attempts to kick him out, but he and his friend Kishida overpower and pin her down. Yumi's body has always been an object of desire—Yoshihiko, in particular, has long harbored a secret fascination with fisting. Driven by lust, Yoshihiko and Kishida begin to torment Yumi's groin, slowly increasing the number of fingers to heighten her pleasure. Overwhelmed by a mix of fear and arousal, Yumi writhes in agony yet endures their assault. Finally, Yoshihiko's clenched fist plunges deep into her crotch.