Joel Demetrius is quite looking forward to moving in with his new step-family, but as far as his sister Cassie's concerned, they're nothing but intruders. She doesn't want anything to do with Gerald and his two sons, and to make matters worse their new home is a derelict old house, neglected for decades. Joel thinks it's interesting. Cassie thinks it's a dump.

But his sister isn't the only reason the house doesn't feel like a home. As fascinated as he is by the place, Joel has to admit there's something not quite right about it. Not only does he keep seeing things out of the corner of his eye, but his sleep is plagued by nightmares. He can't seem to stop dreaming about a terrified boy who keeps repeating the same fractured prayer:

IF I SHOULD DIE BEFORE I WAKE, I PRAY THE LORD MY SOUL TO TAKE . . .

As events in the house become harder and harder to explain, it seems that the line between nightmare and reality is getting steadily more blurred. And when the battle between Cassie and her step-brothers draws everyone deeper into the mystery, all four kids are forced to confront the question of just who the intruders really are.