Park Dong Won, a common man, and his family move into a house purchased after 11 years of labor. They throw a housewarming party and invite all their friends. A heavy overnight downpour creates an extremely big sinkhole, and in a mere minute, it engulfs the whole house with the people inside it. Deep down the hole, Park Dong Won, his neighbor Jeong Man Soo, and the guests have to find a way out. As the luck would have it rain again begins to pour down, filling the sinkhole with water. They must find out a solution before time runs out to survive.