The film's prologue takes places in an area of rural farmland in Dannebrog, Nebraska in Autumn 1996. While there, Bob Irisen – a storm chasing with the National Weather Service – is driving down a country road to track a massive supercell thunderstorm. As a tornado touches down yards away Bob warns a family living nearby, right as the family's daughter Sarah, arrives home from school, about the oncoming twister, which sends them running into their root cellar just before it destroys their farm.