Darkness is a horror movie so vague about the nightmare it’s spinning, it seems scared of its own shadows. Forty years ago, a group of children were brought to a country cottage, where they were subjected to a brutal ritual something or other, at the hands of evil adults who had a master plan to do…something. Terrified yet? We know that the house is haunted, because the family who’s just moved in has to deal with the lights always flickering out. They should have called the movie The Fuse Box Horror. Darkness was clearly tossed together like salad in the editing room, since it’s little more than the sum of its unshocking shock cuts. As the mom in distress, Lena Olin, trying on an American accent, looks ready to star in some radical spin-off of Desperate Housewives where the characters are actually allowed more than one facial crease and idiosyncrasy apiece.