The story centers on a corporate climber who gets stuck working late on Christmas Eve and finds herself the target of an unhinged security guard. With no help in sight, the woman must overcome physical and psychological challenges to survive.
When she gets down to the parking garage, she discovers that her car won't start. Her garage is deserted and her cell phone doesn't get a signal underground. When Thomas, a friendly security guard, comes along and offers to help, Angela nervously accepts his gesture of good will. Soon after a failed attempt to start her car, he invites her to stay and share a small Christmas dinner he's preparing in the parking office, but she laughs it off. Angela doesn't realize this is no laughing matter. Thomas has been watching her closely--for months. His dinner invitation is not optional. If Angela wants to live to see Christmas morning, she must find a way to escape from level P2 of the parking garage.