Dong-won and his family move into a house bought after years of hard work and savings. Filled with happiness, he invites his colleagues for a housewarming party, but the heavy rain during the night before has created a gigantic sinkhole, and in a mere minute, it swallows up the whole house and the people inside. Hundreds of meters down the hole, Dong-won, his neighbour Man-su, and the unfortunate guests must find their way out. Rain starts to pour down, filling the sinkhole with water, and they`re running out of time.