Yu lives alone at a boarding school. Her fulfilling student life has come to an end, and it's finally her graduation ceremony. On her way home, feeling a bit lonely, it was her mother-in-law, Wasaki, who came running up to her with a smile on her face. Delighted to be reunited with the woman of her dreams, the two of them celebrate graduation together at night... The two of them talk to each other to make up for the time they were apart. Then, ``My gift to you, Yuu-kun, who has grown up...'' Wasaki's slightly wet lips quietly covered his lips... On this day, I was climbing the stairs of adulthood yet again.