Three years have passed since Yuu entered a boarding school due to her father's remarriage. On her graduation day, as she heads home with friends, she's surprised to see someone running toward her with a bright smile—it's her former stepmother, Yuna. Overjoyed at their long-awaited reunion, the two spend the evening together to celebrate her graduation. But Yuna gets carried away with celebration and drinks too much, leaving Yuu to take care of her. Feelings Yuu once harbored for the woman she admired begin to resurface, impossible to suppress. And so, Yuu takes another step forward into adulthood.