After three years at a boarding school, Yu's fruitful student life is finally coming to an end, and he is graduating. Yu is filled with gratitude for the support he received from his stepmother, Airi, a woman he admires, who has helped him get this far. However, he receives a message from her saying that she cannot attend the graduation ceremony... And on the day of the ceremony, the woman who waves at him with a smile from across the street is none other than Airi! He runs up to her in joy, and with a gentle smile she says, "Let's celebrate your graduation together tonight..."