Mikoto Shiratori and her companion Yamato encounter the formidable Demon Lord during a hunt. Using overwhelming magic and sadistic pleasure, the Demon Lord breaks Mikoto's will, forcing her into a state of submission. Despite her struggle to remain loyal to Yamato, Mikoto is violated and claimed as the Demon Lord's concubine, leaving her shattered and guilt-ridden.
After Mikoto attempts to protect Yamato by striking a deal with the sinister Lord Nightmare, she is subjected to his cruel domination. Yamato is soon drawn into a nightmarish dream realm, where he discovers that both Mikoto and Sui have been broken by the villain's psychological and physical torture. As the girls succumb to the pleasure and power of their captor, Yamato is forced to witness their corruption in a prison where resistance seems futile.