Recently, his mother Eriko has started a no-bra fitness regime. With her nipples flashing at every opportunity, her son Takeshi can't help but think of Eriko as a woman. Takeshi uses all his rationality to suppress his lust for Eriko. However, there is a limit to everything, and in his burst of lust, he relentlessly caresses Eriko's nipples. She rejects him at the last moment and he doesn't cross the line... but from then on, Takeshi becomes abnormally obsessed with Eriko's nipples...