After leaving his family home for three years and living in a dormitory at a distant school, Yuu. Then, on the day of his graduation ceremony that marked the end of his school life, his stepmother Marina rushed to him with a face full of overflowing smiles... That night, during their private graduation celebration, Marina, overwhelmed with joy, drank too much and passed out. Then, as he escorted her to her accommodation, she guided his hand gently to her chest as a graduation gift... Guided by his beloved stepmother, Yuu ascended another step into adulthood.
