Diane is a repressed, neurotic grad student, who moves into a cursed mansion only to be possessed by the house's demonic master. She is then transformed into a raven-haired, leather and lingerie-clad seductress, who seeks a virgin sacrifice for her master. Meanwhile her sister, brother-in-law, a priest, and a pizza boy try to rescue her while avoiding the demon's wrath.

导演TJ正在导演一部科幻片《火星坏女孩》，但是却很不顺利，请来的女主角不是被杀就是失踪。一时间人心惶惶，没有人敢出演女主角。制片方最后不得不请来色情小说作者艾曼纽担当主演，开始重新拍摄。但是凶杀并没有结束，相反这次凶杀的魔爪不只是伸向了艾曼纽，剧组的其他人员也命悬一线...