This dark British drama features S&M and centers upon a woman who slowly, fatally tortures the man she keeps captive in her basement.
Anne Marie, a French woman, finds her captive, Tevin, in a bar. She is beautiful and he willingly returns to her apartment for a night of love. Instead she spikes his drink. He awakens to find himself stripped to his underwear and strapped to a dentist's chair.
Enter Anne Marie, dressed in full dominatrix garb. She swiftly begins a series of vigorous mental and physical tortures. An unseen third person videotapes the festivities.
Anne-Marie is soon replaced by the camera woman and true perpetrator, Julia, a serial killer. For her good work, Anne-Marie is butchered and her head is placed in the cellar with Julia's other victims.
Julia proceeds to continue tormenting Tevin until the film's inevitable conclusion.........[borrowed from NYTimes movie review]