In the innocence of childhood, fear is perfect—untempered by adult rationality, which supposes that we can fully comprehend the world around us.
Following the breakup of his marriage, Steven LaChance is not surprised when his children begin having nightmares. Shadowy manifestations of their worst fears appear in the closets and basement of their home in Union, Missouri—but he believes they are simply reacting to the loss of their mother. Then Steven himself begins to experience strange things inside the house: inexplicable temperature fluctuations, electrical disturbances, and the faint sound of agonized screams. In spite of his rationality, he comes to believe that disembodied spirits are preying on his children.
Steven takes them away from the house, but when another family with small children moves in, he vows to help the innocent face a truth that adults fear to acknowledge: If you enter the world of spirits, the spirits enter yours.