Monami is a mother who dotes on her only son, Kenichi. The bad boys in his class tease Kenichi, calling him a bookworm, but when they see Monami's large breasts, their groins throb. The cunning Ryuji forces a pornographic book on Kenichi and lies to his mother, saying that he told Kenichi to cheat by saying, "Kenichi, I'll show you my exam paper, so give me the pornographic book." Shocked, Monami has no choice but to listen to Ryuji's orders to protect Kenichi, and he ends up fondling her large breasts and even making her have sex with him, just like he did with the pornographic book. The naughty boys' torture escalates, and the busty mother becomes obedient to their dicks like a toy.