Nanako falls in love with Komugi and she joins a seminar which he enrolls, but the seminar is an abnormal seminar. Sexual harassment-like assignments and eccentric classmates confuse her.

Hen Semi (変ゼミ, Hen Zemi), also known as Abnormal Physiology Seminar, is a Japanese comedy manga series written and illustrated by TAGRO and is a remake of his earlier manga series, Hentai Seiri Seminar (変態生理ゼミナール, "Abnormal Physiology Seminar"). Hen Semi has been serialized in Kodansha's Morning 2 manga magazine since 2006. It has been adapted into an original video animation in 2010, as well as an anime television series in 2011.