After walking out on her unstable mother (Maria Bello) following a childhood beset by nightmares, troubled Rebecca (Teresa Palmer) reluctantly returns home for the sake of her young half-brother Martin (Gabriel Bateman). It seems Martin is being terrorized by the same spectral presence that used to prey on Rebecca as a child - a malicious entity that only ever appears in the dark. She's called Diana. And she's determined to keep the lights off... Throw back the curtains and check your torch batteries as writer-director David F. Sandberg flicks the switch on a creepshow that delivers more jolts than a wet finger in a plug socket.