Operation 05: Seek I (Slave Girl Marino) - S1.E5

The story begins when an ordinary girl named Marino Okura-(a virgin) is being chased by two young men who are revealed to be human traffickers. After getting captured, she is then shown in their car nervous and scared. When she attempts to escape, she is pulled back and brought into the estate of the dominatrix Saki and her unnamed master. Saki and her master spend the episode training Marino to be their sex slave, a process which involves Marino being forced to perform various sex acts and submit to the demands of her masters. As the episode progresses, it becomes apparent that Saki's current master is actually the son of her original master, now deceased. Saki's original master made a living as a world-famous bondage artist. This, however, was only his public face. His true face was that of a masochist female dominator. The episode culminates with Marino being left chained in a cell to await her next "session".