London is in chaos. A military cargo plane has crashed leaving its highly classified contents strewn across the city. Completely unaware London is in lockdown, Charlie (Noel Clarke) and Shelley (Antonia Campbell-Hughes), accompanied by best friends Mark (Colin O'Donoghue) and Nikki (Laura Haddock), are at Storage 24 dividing up their possessions after a recent break-up. Suddenly, the power goes off. Trapped in a dark maze of endless corridors, a mystery predator is hunting them one by one. In a place designed to keep things in, how do you get out?