As he entered his third year at the boarding school, his rich student life was coming to an end, leaving him eagerly anticipating new beginnings. On the day of their graduation ceremony, his heart leaped with joy when his stepsister Ayaka, also known as his stepmother, ran up to him with a smile. She invited him to celebrate their graduation together, unable to hide her excitement about reuniting with her secret crush after so long. They spent time catching up, sharing stories, and reminiscing about their past. Finally, she leaned in gently and kissed him on the lips, calling it a present for the grown-up version of himself. And just like that, he took another step towards adulthood.

寮制の学校に入って3年。実りある学生生活も終わりを迎え、新たな旅立ちに期待を膨らませるゆう。そして卒業式当日、彼のもとへ笑顔で駆けよってきたのは、義母・あやかであった。密かな想い人と久々の再会に喜びを隠せないゆうに彼女は「2人で卒業祝いしよ」と誘い…。離れ離れだった時間を埋めるかのように語り合う2人。そして「大人になったゆう君へのプレゼント」と彼女は優しく彼に口づけを…。そして彼はまた、大人への階段を上るのであった。