It's been a year since his father left for work and didn't come home. His mother, Natsumi, acts strong, but Yuta knows that she is lonely Kokoro. How can he, her son, comfort his mother? Day after day passes without him being able to find the answer. Then, Yuta witnesses Natsumi indulging in masturbation and sobbing after orgasm. Seeing his mother's sad state, Yuta makes a decision. He will embrace his mother in place of his father.