Manga by author U-jin

A Keio College (top notch Tokyo college) exam candidate, Touma Inaba, is interupted when a cute young girl, Urara Kasuga, arrives at his hotel room door. She later turns out to be his cousin who he barely remembers from his childhood. Urara, who had felt something special for him (an other-than-cousinly-love), invites Touma to live with her since he has no place to stay other than the hotel room. Before taking the test, Touma meets Meiko Yotsuba, a beautiful, sophisticated woman also trying to get into Keio. Meiko gets into Keio but Touma does not, due to a cold Urara had given him shortly before. Although he did not make it, he pretends he does to earn the respect of Meiko. Touma is caught up in a love triangle with Urara and Meiko, while struggling to keep Meiko believing he's really a Keio student and still be there for Urara at the same time.

Gakuen Heaven is the story of Oshino Makoto in his attempt to become a teacher, in order to fulfill a promise made to his childhood friend and first love Koiwai Ayano, who also promised that when they see each other again they will get married. Unfortunately, he fails miserably and ends up as a substitute teacher in an all-girls private school governed by his grandmother. He meets a lot of female students there, especially Narusawa Tsugum; as well as a teacher who resembles his long lost first love, Asagiri Ayano. He even becomes the love interest of the substitute principal, his cousin Kyoko.