In the past, Katou was the cute idol Ruka. However, it is a past he wants to erase, due to having outgrown his idol image and a certain incident. Now, Katou's is hiding as a plain, loner college student. Unfortunately, Katou's peaceful campus life is destroyed by the appearance of his former idol partner Aki, who threatens to expose Katou's identity as Ruka and a virgin.
Ore no Shitsuketa Doutei-chan