Beautiful Sisters: Flesh Slaves (1986)
Original title: 美姉妹肉奴隷
Beautiful Sisters: Flesh Slaves is a 1986 Japanese-language horror movie directed by Katsuhiko Fujii, with a running time of 1h 10m. It stars Rei Akasaka, Megumi Kiyosato and Kiriko Shimizu.
A man on the run from the police takes two sisters hostage in their dental office apartment. He makes himself at home sexually abusing them and getting food service. But the sisters are resilient and quietly develop a plan for revenge.