Cage

When two sisters both start a job at a quiet high school, little did they know they were stepping out of the ordinary and into the perverse. It seems that the school they were assigned to is ran by a cabal of perverted teachers and students, who have every intention of keeping the status quo of orgies, public nudity, and sexual slavery at their school alive—and they're eying the two pretty new teachers who just showed up as recruits, whether they want to join in or not!

(Source: MU)