After a powerful storm in Oklahoma takes the lives of her parents, Dr. April Saunders (Mimi Rogers) dedicates her life to studying tornadoes and finding better weather systems to track them.  On a trip to Seattle with her teenage daughter, she stumbles upon a supercell that begins to cause rare and forceful tornadoes in the area.  When her daughter is caught in a dangerous twister, April must find a way to save her and an unprepared city from destruction.