Two mentally ill women who are clearly suffering from not otherwise specified delusional disorders, a mother and a (grown) daughter, live together in a secluded mansion. They are in a relationship and both are recognised for their beauty. They spend their days playing perverse BDSM-related incestuous games in memory of their sadistic patriarch who, when he was still alive, raped his daughter when she was eleven, murdered several servants, and is now a mummified corpse with which the daughter is shown having sex. They occasionally kill their servants and bury their bodies in the garden.
When first glimpsed the psychotic mother-daughter protagonists, half-dressed, are burying their disemboweled chauffeur in a pit they have just finished to dig in their backyard on a dark and stormy night under the thunder and heavy rain. They lay a shovel and drag out of the bushes his fresh corpse, put to death in one of their usual games combining incestuous sex with murder. Shortly after this and at first unnoticed by the two women a lovesick detective pulls his car up to the residence, suffering from a painful bullet wound and an equally painful yearning to track down Laura, his long-missing beloved for whom he has been searching for three years and about whom it is known that she has visited the area. What he does not know is that he has stumbled onto the lair of two profoundly insane women who have already lured Laura into their home and brutally killed her (in the process decorating their kitchen with her viscera, as a flashback helpfully shows). It is also revealed that the daughter is physically very similar to Laura and is desperately looking for a man’s companionship. The film’s protagonist’s search for a woman named Laura is a direct reference to the classic film noir Laura (1944) by American director Otto Preminger. The film uses as background music, in addition to classical music by Sergei Rachmaninoff and Giaches de Wert, the compositions used by Glenn Miller and Julie London in Laura (1944).
The duo then easily take the seriously wounded and bleeding detective, having already figured them out to be responsible for Laura’s kidnapping, into their home, essentially kidnapping him. As the exhausted detective was silent and apparently refuses to speak, even in order to state his own name, the two women christen him Singapore Sling after they discover a recipe in his pocket notebook for that type of cocktail and seem quite content with that arrangement. They use him as a pawn in their sexually tinged role-playing games and as a party to their distorted and perverse form of entertainment, during which Singapore Sling, now a prisoner, is tied up, chained to a bed, vomited on, electrocuted, used as a sex slave, and subjected to various other forms of torture and atrocities in which he is forced to participate. However, as Singapore Sling’s confinement wears on he regains his strength and takes a more active role in the games. His deranged captors become concerned and alarmed when a sharp kitchen knife, belonging to the late father, goes missing and they discover Singapore Sling digging a deep hole in their backyard. As psychotic as these two are, they are still lucid enough to recognize that a killing is imminent, if not two or even three. In an atmosphere of decadence and dark madness, the characters gradually sink into the depths of their subconscious mind.
A few days later the daughter decides that she is fed up with having to suffer under the yoke of maternal authority, and, together with Singapore Sling, murders her mother. Singapore Sling then takes what up until now used to be the mother’s role in the sexual games. However, during one of these games, a reenactment of Laura’s murder, he stabs the daughter, playing Laura, with the aforementioned missing kitchen knife now attached to his penis. The daughter, while bleeding to death, shoots Singapore Sling and then he goes out to the garden and falls into the pit which he himself had recently dug. The film hence ends, in short, with all three characters dead.