Jennifer and Paul Hemdale have just moved into their dream house. But their happy marriage is about to be put to the test as they slowly discover the secret behind the Black Room in the cellar. Something else is already living in the Hemdales’ new home and it is growing stronger every day. It has claimed many victims including the last owners of the house. It is an evil supernatural entity that is determined to destroy everyone in its’ path. Repairmen who journey down into the basement soon meet a horrible end. When Paul tries to get to the bottom of this, he is soon taken over by this demonic entity. Now in human form, it is no longer trapped within the walls of the Black Room and is quick to take advantage of all carnal pleasures of the flesh. Women are the victims of choice for this rampaging hell spawn. Jennifer and her younger sister, Karen, begin to suspect that something is wrong with Paul. Karen finds out the truth a hard and painful way, leaving Jennifer alone to fight the demonic entity that has possessed her husband and threatens to destroy her very soul.