The novel opens with a description of the small town of Moore, Oklahoma, on a hot and humid summer day in May 1999. The town is full of people going about their daily lives, unaware of the impending disaster that is about to strike.
The first sign of trouble is the appearance of a strange, dark cloud on the horizon. The cloud quickly grows larger and darker, and soon the entire sky is black. The wind picks up, and the rain begins to fall in torrents.
The people of Moore are caught off guard by the sudden storm. They rush to take shelter, but many are not fast enough. The wind and rain are so strong that they knock down trees and power lines, and even destroy entire buildings.
The storm leaves a path of destruction in its wake. Dozens of people are killed, and hundreds more are injured. The town of Moore is in ruins, and it will take years to rebuild.