Long ago, Fujishiro Kosuke promised his love to his childhood friend, Sayaka-chan. But his pledge to save his first sexual experience for her takes a shocking turn when he's suddenly abducted and thrown into a secret prison -- run by beautiful, terrifying women in fetish gear. His seductive kidnappers claim to have a higher purpose but are after one thing: Kosuke's virginity, and they're willing to employ every kink at their disposal. Who are these women, and why are they trying to break Kosuke's promise to Sayaka-chan?