ANew York book editor Will Atenton (Daniel Craig) and his family -- wife Libby (Rachel Weisz) and two daughters, Trish (Taylor Geare) and Dee Dee (Claire Geare) -- move into their dream house in the quaint Connecticut town of New Ashford. When Dee Dee sees a man looking in a window and Will finds teenagers congregating in his basement, he looks into the history of the house only to discover that it was previously inhabited by the Ward family and that father Peter Ward is said to have murdered his wife Elizabeth and two daughters, Katherine and Beatrice. A bit of research on Will's part reveals that Peter Ward spent five years in Greenhaven Psychiatric Hospital and has recently been discharged. Fearful that Ward may be stalking his family, Will attempts to track him down. Neighbor Ann Patterson (Naomi Watts) may hold some answers, but those answers are about to change Will's reality.
AAnn warns Peter that he must get out of the house or go crazy there, and he suddenly remembers the events on the night that Libby and the girls were murdered. He was on his way home, talking to Libby on his cell, when a man entered the house carrying a gun. Peter raced home and struggled with the man who, it turns out, was hired by Jack to kill Ann but he got the wrong house. Libby, who has already been shot, grabbed a gun and tried to shoot the hitman but the bullet grazed Peter's temple. Just as Peter realizes that he wasn't the one who shot Libby and the girls, the door opens and Jack walks in, followed by the hitman who starts beating up on Peter. While Libby watches helplessly, Jack chloroforms Peter and pushes him down the basement steps. He then shoots Boyce, ties up Ann, and sets the house on fire. Libby wakes up Peter then distracts Jack by tinkling the bells long enough for Peter to knock him out, untie Ann, and carry her outside. Peter then goes back inside the burning house to find the ghosts of Libby and the girls. He kisses them goodbye, and Libby assures him that she will always be with him. Peter retrieves his book from under the stairs and runs outside as the fire consumes his dream house. In the final scene, Peter is walking down a street in New York. He passes a bookstore where his new book, Dream House, is on display in the window as a #1 National Bestseller.