Captured for Sex 2 (1986)

A young man, Shingo, and his girlfriend, Miki, are driving in the countryside when their car breaks down. When they go and seek help from a nearby house, they are captured and kept as sex slaves by an unnamed man. Gradually Shingo becomes enraptured by the acts of forced S/M on both himself and Miki and offers to be the man’s apprentice, helping him abduct and torture two other women. And soon, the apprentice wishes to become the master.