After the graduation ceremony... a gift from my stepmother to you as an adult.

For three years since leaving her family home, Yu has been living in a dormitory at a school far away. And on the day of the graduation ceremony, which marks the end of school life, stepmother Marina runs up to him with a tingly smile... That night, Marina, who drank too much joyously as a graduation celebration, was drunk and was drunk. He then sent him to his accommodation as a graduation gift, and gently led his hands to his chest... Guided by her dream stepmother, Yu goes up another adult stairs.