It's been three years since I started a boarding school. Yu's fruitful student life is coming to an end, and she is excited about her new journey. And on the day of the graduation ceremony, it was his mother-in-law, Ayaka, who ran to him with a smile. - Yu, who can not hide her joy at reuniting with her secret lover for the first time in a long time, invites her to "celebrate graduation with the two of you". The two talk to each other as if to fill the time they have been apart. And she kisses him gently, "A gift for Yu-kun who has grown up." And he was also climbing the stairs to adulthood.