A seemingly ordinary middle-class household somewhere in Japan. Yet, there is no sign of the parents. The brother harbors intense feelings toward his sister—feelings that go far beyond mere blood relation. His obsession is focused entirely on one part of her body: her buttocks. He is fixated on touching her ass, sniffing its scent, tasting it, and savoring its texture. He photographs the prominent curve of her buttocks visible beneath her school uniform, then thrusts his throbbing cock into her slit as she rides his face in a vigorous cowgirl position. The sister willingly participates, even letting him strip and tear off her clothes, anoint her peach-like ass with oil, and proudly display it to his friends. This disturbing tale explores the twisted bond between siblings. A controversial work composed of four chapters, unfolding a deeply unsettling atmosphere.