"Eri... will you become my family?" Ryota lost his mother at a young age and grew up without knowing the warmth of a mother. It was inevitable that he would develop feelings for the woman close to him who exuded maternal love. Ryota became abnormally attached to his cousin Eri, who came to tutor him. "Eri... you had a boyfriend..." Ryota was suddenly informed of this fact during class. The feelings that had been swelling up inside him bare their fangs.