Sei Luminous Jogakuin is a 13 episode Japanese anime series that
originally ran in 1998. In the show, Kaihei (Tetsuya Iwanaga) is left in
charge of his late grandfather's all-girls academy. Kaihei ends up
being the only male at the St. Luminous Mission High School, and is
forced to try to solve the case of a missing person without involving
the local police. Unfortunately, he only has until graduation to get the
job done. Kenji Terada provided the original story.