Two parents mourning the recent death of their young son fight a gang of masked prowlers during a violent home invasion. Their marriage dissolving in the aftermath of the unthinkable, a grieving novelist (Milo Ventimiglia) and his devastated wife Sarah Shahi) are awoken one night by frantic knocking at their front door. There they find a terrified young girl (Sarah Paxton) who claims she is being stalked though the darkness by masked assailants. Concerned, the couple quickly invites her in and starts asking questions. Before their shell-shocked guest can answer, however, the intruders have arrived. They're determined to get inside, and once they do, no one will be safe. Meanwhile, the terrifying truth about mysterious invaders slowly comes to light.