A young woman named Lilly wakes up in her living room, unable to recall the events of the previous night she had with her boyfriend Darren. After seeing that all of her furniture and belongings have gone missing; leaving her with nothing but a simple briefcase. She then discovers that all of the doors and windows of her house have been mysteriously boarded shut, much to Lilly’s shock and horror. This leaves her trapped alone, a prisoner in her own home. She soon starts discovering clues left inside each room of the house that lead her find the combination to the briefcase. After much trial, error and frustration she finally finds all three numbers of the combination and opens the case to find a key inside. It fails to open the front door, but Lilly successfully uses it to open her padlocked bedroom. She finds her bedroom empty, only containing a pile of her clothes and the only open window in the house. Having no other means of getting out of the house, Lilly ties all of the clothes together into a rope and uses it climb out of the window and down the side of the house. Unfortunately, the rope doesn’t hold and breaks, she injures herself after falling to the ground. Lilly sees the lights in her garage on and just barely manages to drag herself towards it; only to be greeted by Darren. He congratulates her for finding her way out the house; before drugging her as she tries to escape.
The story ends with the rooms of the house reset to how it was during the beginning of the film, as a different woman wakes up in the living with the briefcase, unable to remember what happened the night before; as Darren watches through a hidden camera, timing her progress.