A young couple (Patrick Wilson, Rose Byrne) have just moved into their new home when their young son (Ty Simpkins) suddenly sinks into an inexplicable coma; soon other inexplicable (and terrifying) things begin to happen, driving them into another house—but the haunting follows them. Leigh Whannell’s script is a Paranormal Activity knockoff, but with new wrinkles, a truly creepy atmosphere (courtesy of director James Wan) and a number of delicious chills. It’s efficient, imaginative and effective, but with a catch: There’s the usual non-ending that always makes movies like this so dispiriting. The filmmakers are so determined to leave room for a sequel that evil triumphs and good is not allowed to prevail. Barbara Hershey plays Wilson’s mother, Lin Shaye a psychic called in to help.