London is in chaos. A military cargo plane has crashed, leaving its highly classified contents strewn across the city. Completely unaware London is in lock down, Charlie and Shelley are at Storage 24, dividing up their possessions after a recent break-up. While Shelley and best friend Nikki are there to close the book on the relationship, Charlie sees the meeting as an opportunity for reconciliation and has brought along best friend Mark to help.
However, the presence of Shelly's friend Chris, adds more fuel to the fire. Charlie thinks that Shelly is having an affair with Chris. Just when emotions begin to get out of hand, the power suddenly goes off. With the atmosphere already tense, the group quickly gather that they have a much bigger problem at hand. Trapped inside the building, they soon realize they are not alone.
Caught in a dark maze of endless corridors, they find themselves being hunted down one after the other by a mysterious predator. In a place designed to keep things in, how do you get out?