Fallout 2 is once again set in and around California and the Core Region, in the year of 2241.
The Chosen One, the grandchild of the Vault Dweller is a resident of the small tribal village of Arroyo. Having suffered a terrible drought, the village elders task the Chosen One to collect a GECK, a pre-war device designed to create communities out of the post-apocalyptic wasteland.
After discovering the remnants of Vault 13 and subsequently returning to Arroyo, the player discovers that is has been captured by the remnants of the United States government, a group calling themselves the "Enclave". Through various means, the player finds a way onto the Enclave's main headquarters, discovering experiments with a pre-war virus along the way. The player destroys the Oil Rig headquarters, and escapes with the captives and the GECK back to Arroyo, to start a thriving new community.