Toko, the mother of Shota's friend Miyoshi, is known for her voluptuous figure, especially her particularly attractive buttocks. To prove her allure, Miyoshi invites Shota to their home. Toko's buttocks possess a perfect silhouette and softness, and Shota instantly falls for her upon seeing her for the first time. After that, Shota begins frequently visiting Miyoshi's house with the sole intention of touching Toko's buttocks. His cunning mind and growing curiosity deepen his obsession with Toko, driving the story into increasingly intense territory.