Female Prison Guards: The Lustful Females in the Cages (1997)

Kaoru, who wants to be a photographer, is overworked as an assistant for a low salary. Misaki, a senior assistant, can't stand to see Kaoru crying after being bullied by the photographer, so she invites him to live with her. Kaoru soon falls in love with Misaki's younger brother Shinobu, and the three of them seem to be living together smoothly, but then Kaoru sees Misaki and Shinobu embracing each other...