A female investigator, Yuki, is captured by an enemy agency together with her sister. They are locked up in a dimly lit basement called the interrogation room, where they are subjected to a horrific SM interrogation in which pleasure and pain become one and the same.

No matter what is done to Yuki, she never gives in. However, her sister has already been transformed by the training and attacks Yuki together with the interrogator.

What will be the fate of the two busty female agents who have nowhere to run?