Centers on the events leading up to the cataclysmic 1980 eruption of Mount St. Helens in Washington, with the story beginning on the day volcanic activity started on March 20, 1980, and ending on the day of the eruption, May 18, 1980.

After his family moves to a new house, a young boy discovers a mysterious book that details a curse hanging over the date of Saturday the 14th. Opening the book releases a band of monsters into the house and the family must join together to save themselves and their neighborhood.