Wana - Hakudaku Mamire no Houkago

After the sudden death of her brother, Raika decides to transfer to the same school to investigate the circumstances of his death. Since his brother attended an all-boys school, she needs to disguise herself as a boy. She discovered there's something more in her brother's school. But her cover is blown and the boys fucked Raika and loses her virginity and become their sex slave. But she's get more deeper into the investigation and she discover more.