In the year 2077, a nuclear war erupts between the United States and China. In Massachusetts, the protagonist and their family—consisting of their husband Nate or wife Nora, depending on the player's chosen , and their baby son Shaun—escape into Vault 111, gaining entry due to a Vault-Tec representative signing them up for it immediately prior to the bombs dropping. Inside, the family members are tricked into entering cryogenic pods and frozen alive. 150 years later, the protagonist's spouse is killed and Shaun is taken away by a mysterious group. The life support system malfunctions at a later date and unfreezes the protagonist, who leaves their pod, realizing they are the Sole Survivor of Vault 111 as the remaining residents are deceased. They emerge from the vault into a wasteland now known as the Commonwealth.
