On a cold, stormy late-fall night, Jamie and her hospital coworkers start the second shift, unaware that the night will soon spiral into a terrifying ordeal. News of a murderer on the loose and an accident set off a series of unnerving events, as a sense of unease settles over the building. While the storm rages outside, the hospital becomes a place of increasing danger, with something—or someone—lurking in the shadows. With every passing hour, Jamie and her colleagues find themselves drawn deeper into a chilling mystery, as they realize that the threat they face may be far closer than they could have ever imagined.