Gabriel Bateman and Teresa Palmer in Lights Out.

Three years ago, director David F. Sandberg made Lights Out, a great short about a woman, home alone at night, who kept noticing a dark figure when she switched off the light. The payoff was both hilarious and scary as shit.

So, of course, producer James Wan got hold of Sandberg, and now there’s a full-length feature film based on that light-switch premise. Writer Eric Heisserer takes the idea, fleshes it out, and comes up with a pretty good story to go with Sandberg’s strong horror-directing abilities.

Rebecca (Teresa Palmer) is an angry woman with mommy and commitment issues. Her mom, Sophie (Maria Bello), recently lost her husband and has fallen into a depression; she is talking to herself. Rebecca’s younger brother, Martin (Gabriel Bateman), is seeing a strange dark figure when the lights go out. It all leads up to a finale during which flashlights are very valuable, and potential victims behave like idiots.

Sandberg repeats the same jolt scare over and over again, and makes it all work nicely. The film is genuinely scary in the moments when it’s trying to be scary. The background story is a little on the flaccid side, but Palmer and Bello are good in their roles, and Bateman plays a scared kid with major aplomb. It’s a serviceable horror film that will give genre fans a reasonably good time.

Lights Out is playing at theaters across the valley.