After three years at a boarding school, adult student Yu is finally graduating. He knows he made it this far thanks to his beautiful stepmother Airi, the woman he has always admired, but is disappointed when she says she cannot attend the ceremony. On graduation day, however, he spots Airi smiling and waving from across the street. As he rushes to her in delight, she softly suggests that the two of them celebrate alone that night, leading to an intimate graduation gift.