The main story involves a dysfunctional family, who are particularly in dire trouble now that the depressed mother, Sophie, has begun to exhibit signs of mental illness that she thought her medications had all but completely eradicated. Sophie's first husband has gone missing under mysterious circumstances, though we get to see that hubby number two is actually brutally murdered by a supernatural force while in his workplace there's barely a mention of this event among the family afterward, curiously). Sophie's daughter, the long-suffering Rebecca, no longer chooses to visit her now that she has taken a turn for the worse, leaving Sophie's young son, Martin, in a very vulnerable spot, all alone with a sick mother and an entity that she is always talking to in the shadows. As Martin reaches out for help, half-sister Rebecca gets thrust back into the family issues that have haunted her over the years, having to get to the bottom of the jealous evil presence in the house that her mother has called "Diana", who lives and kills in the dark recesses of the house.