In this prequel of a sort to The Amityville Horror (1979), the dysfunctional Montelli family moves into their new home and finds many curious things right away, including every window being nailed shut and a secret room in the basement of the house that is full of flies, muck and smells to high heaven (or down to low Hell). The longer they stay, the more they begin to witness strange events, and bicker violently with one another, until the eldest son of the family, Sonny ( Jack Magner), actually begins to exhibit behavior that may not be his own, including a desire to kill his abusive father, Anthony (Burt Young), and defile his younger teenage sister, Trish (Diane Franklin). Before things get completely out of hand, the mother requests that a local priest, Father Adamsky (James Olson), come out to investigate the supernatural events of the place, but without the backing of his superiors, he's going it alone against what appears to be a portal to unfathomable evil that resides below the house. Rutanya Alda and Andrew Prine also appear. Directed by Damiano Damiano from a script by Tommy Lee Wallace.