In 2077, nuclear war erupted between the United States and China. Most of the people on Earth died, and the world became a desert. Fortunately, the United States government had already built underground fallout shelters called "Vaults," where some of the people went to survive. The player character was born in Vault 13, in what had been California. The people living in the vault were too scared to ever come out of the Vault, so they stayed inside it for 84 years. 