It's Christmas Eve at the luxurious 108-storey Tower Sky twin tower building in central Seoul. Residents and staff members busy themselves with the upcoming Christmas party that night. Helicopters are hired to circle the building and spray a spectacle of snow during the Christmas celebrations. Their amazement soon turns into terror when one of the helicopters loses control, crashing into the building, setting off a chain off horrifying events that threatens the lives of all the residents.
