Here's the official rundown:
A man (Sharlto Copley, DISTRICT 9, ELYSIUM) wakes up in a pit of dead bodies with no memory of who he is or how he got there. Fleeing the scene, he breaks into a nearby house and is met at gunpoint by a group of terrified strangers, all suffering from memory loss. Suspicion gives way to violence as the group starts to piece together clues about their identities, but when they uncover a threat that's more vicious—and hungry—than each other, they are forced to figure out what brought them all together—before it's too late.
Open Grave will air on VOD on December 24th, and open in theaters on January 3rd, 2014.