Nishi Koukou 1-nen A-kumi, Sugawara Kai-kun wa 20-sai.
Kai, a Freshman in High School, Is 20 Years Old.·西高校1年A組、菅原海くんは20歳。
A student develops feelings for Kai Sugawara, a classmate who appears older and composed. One evening, the student spots him at a bar with adults and becomes concerned that he may be drinking underage. When confronted, Kai claims to be 20 years old. The student is shocked but agrees to keep the secret after Kai kisses them in a mature manner. The next day, they struggle with how to act around him.
