This is one volume of the Ryokunohara Gakuen Series.

Other volumes in the series:
1: Rapyutasu Ryuuseigun
2: Psicron Syndrome
3: Hiroki - Harusaki Meiro
4: Anata - Mahoroba Festival
5: Lunatic Cinema
6: Human Nore no Koe
7: Winter Locket
8: Aoi Ginga no Yoake