Six Masters Island: Perverse Intentions

The twins always had dominant tendencies, and after the death of their parents, they are not slow to explore sex with their nanny, Sarah. Soon after, they begin to train Sarah as their sex slave, but they want much more. Practising their newly discovered BDSM arts on Sarah, they abduct a new girl, much younger than Sarah, to become their slave. And that is only the start of it"?