Wolf Tanaka, a man of restraint, finds his resolve crumbling as he watches his stepsister, Ren Usui, prance around their home, her young, firm body on full display. Her every move ignites a fire within him, and before he can stop himself, he's succumbing to his desires. Ren, oblivious to her brother's struggle, continues her innocent provocations, unknowingly pushing Wolf closer to the edge.