Being afraid of the dark is a familiar childhood anxiety that has exploited in terrifying proportions in the horror genre. "Lights Out" knows how to cash in on the panic that can assail the mind when the lights go out. Bad things happen in darkness and "Lights Out" lays it on thick, even though the story is set in Southern California, which is drenched in megawatts of sunshine.

This is a debut feature by David F. Sandberg who based "Lights Out" on his own, identically titled (and themed) three-minute short from 2013. A much splashier name on the credits, though, is James Wan as producer. According to the production notes, Wan — the man who wrote and directed the first "Saw," and went on to give horror fans such notables as "Insidious," "Dead Silence" and "The Conjuring" — supervised much of the proceedings for "Lights Out." For all that, "Lights Out" is a strangely understated affair. Fans of the genre may go in ready to scream their heads off, but will likely come out relatively serene.

What happened? A desired PG-13 rating, that's what. In a bid to reach a wider audience, we end up with a really compelling storyline but with huge chunks of plot detail and scare factor taken out so as to accommodate the preteen audience.