Three years after leaving home, graduation day arrives, marking the sudden end of student life. On a slightly lonely walk home—perhaps because his parents aren't around—an unexpected figure appears with a warm smile: his stepmother, Yumi. She was someone he had secretly been aware of for a long time, and her sudden appearance fills Yuu with uncontrollable joy. As the two spend time together celebrating his graduation, Yumi gradually becomes tipsy, leaning on Yuu for support as they arrive at their lodging. There, she presents him with a special gift to mark his new beginning. Through this unforgettable day, Yuu takes another step forward into adulthood.