Fifteen years ago, Yuu divorced and took custody of her younger son, Tatsuya. He was her pride and joy, a son she had raised through tireless work and hardship. Now an adult and working professionally, he gifted her a hot springs trip, and the two set off together. On that day, Yuu apologized, saying she had never allowed herself to be weak and had been a terrible mother for not letting him depend on her. Hearing this, Tatsuya held back tears and gently pressed his lips against hers. In that moment, Yuu reached her hand down to his crotch—already erect. She placed her lips on his sensitive flesh, gently tracing it with her mouth. Deep in the mountains of Okunikkō, the bond between mother and son slowly twisted into something unnatural...