What is the plot line for Fallout 1 and 2?

Answer 1

From wiki (BTW: They both have branching storylines, I'd suggest you play them as you won't get the same effect by simply reading their storylines.):

Fallout 1

The protagonist of Fallout is an inhabitant of one of the government-contracted fallout shelters known as Vaults. In subsequent Fallout games, he is referred to as the Vault Dweller. Fallout is set several decades after a worldwide conflict brought on by global petroleum shortage. Several nations begin warring with one another for the last stores of fossil fuels, namely oil and uranium. Known as the Resource Wars, fighting begins in April of 2052 and continues until October 23rd, 2077. China invades Alaska in the winter of 2066, causing the United States to go to war with China and using Canadian resources to supply their war efforts, despite Canadian complaints. Eventually the US annexes Canada in February of 2076 and reclaims Alaska eleven months later. After years of conflict, on October 23rd, 2077, a global nuclear attack occurs. Nobody knows who strikes first, but in less than two hours most major cities are destroyed. The effects of the attack will not fade for the next 100 years. As a consequence, humanity lives in underground Vaults though some people affected by the radiation live topside. The game takes place in 2161 in Southern California and begins in Vault 13, the protagonist's home. Vault 13's Water Chip, a computer chip responsible for the water recycling and pumping machinery, breaks. The Vault Overseer tasks the protagonist with finding a replacement.[6] He is given a portable device called the "PIPBoy 2000" that keeps track of mapmaking, quest objectives, and bookkeeping. Armed with the PIPBoy 2000 and meager equipment, including a small sum of bottle caps which are used as currency in the post-apocalyptic world, the main character is sent off on his quest. The player initially has 150 game days before the Vault's water supply runs out. This time limit can be extended by 100 game days if he commissions merchants in the Hub to send water caravans to Vault 13. Upon returning the chip, the Vault Dweller is then tasked with destroying a mutant army that threatens humanity. A mutant known as "The Master" (previously known as Richard Grey) spreads a pre-war, genetically engineered virus called the "Forced Evolutionary Virus" to convert humanity into a race of "Super Mutants" and bring them together in the "Unity" - his plan for a perfect world. The player must kill him and destroy the military base housing the supply of FEV, thus halting the invasion before it can start. If the player does not complete both objectives within 500 game days, the mutant army will discover Vault 13 and invade it, bringing an end to the game. This time limit is shortened to 400 days if the player divulged Vault 13's location to the water merchants. A cinematic cut-scene of mutants overrunning the vault is shown if the player fails to stop the mutant army within this time frame, indicating the player has lost the game. If the player agrees to join the mutant army, the same cinematic is shown. In version 1.1 of the game, the time limit for the mutant attack on Vault 13 is delayed from 500 days (or 400 depending) to thirteen years of in-game time, effectively giving the player enough time to do as he or she wishes. The player can defeat the Master and destroy the Super Mutants' Military Base in either order. When both threats are eliminated, a cut-scene ensues in which the player automatically returns to Vault 13. There he is told that he has changed too much and his return would negatively influence the citizens of the Vault. Thus he is rewarded with exile into the desert, for, in the Overseer's eyes, the good of the vault. There is an alternate ending in which the Vault Dweller draws a handgun and shoots the Overseer after he is told to go into exile. This ending is inevitable if the player has the "Bloody Mess" trait or has accrued significant negative karma throughout the game. It can be triggered if the player initiates combat in the brief time after the Overseer finishes his conversation but before the ending cut-scene.

Fallout 2

At the end of the original Fallout, the hero Vault Dweller was exiled by the Vault Overseer for his prolonged exposure to the outside world. Unable to return home, the Vault Dweller with a group of willing companions travelled far north. Eventually they founded a tribal village called Arroyo in what is present-day Oregon and lived there for the rest of their lives. 80 years have passed since the original Fallout. In the time since the Vault Dweller's exile, a new government known as the New California Republic (abbreviated NCR) has begun to unify the towns in Southern California and is spreading to the north. A mysterious new organization known as the Enclave has emerged with the most sophisticated technology in the wastes, surpassing even the Brotherhood of Steel. Finally, a new drug, Jet, has become a cancer on many towns with nearly a 100% addiction rate, forcing many to rely on the town of New Reno to keep them supplied. During 2241, Arroyo suffered the worst drought on record. Faced with the calamity, the village elders asked the direct descendant of the Vault Dweller, referred to as the Chosen One, to perform the quest of retrieving a Garden of Eden Creation Kit (G.E:C.K.) for Arroyo. The GECK is a device that can create thriving communities out of the post-apocalyptic wasteland.[4] The player, assuming the role of the Chosen One, is given nothing more than the Vault Dweller's jumpsuit, a RobCo PIPBoy 2000 handheld device, a Vault 13 water flask, and some cash to start on his mission. The player eventually finds Vault 13 (the first place possible to obtain a GECK) devoid of the majority of its former human inhabitants. The Chosen One returns to find his village captured by the remnants of the United States government known as "The Enclave". The Enclave often terrorizes the inhabitants of continental United States with their supreme arsenal of advanced technology. The player, through various means, activates an ancient oil tanker and engages its autopilot, thus allowing him to reach the Enclave's main base on an offshore oil rig. It is revealed that the dwellers of Vault 13 were captured as well, to be used as test subjects for F.E.V. (Forced Evolutionary Virus). Vault 13 was supposed to be closed for 200 years as part of a government experiment,[3] making them perfect test subjects. The Enclave modified the Forced Evolutionary Virus into an airborne disease, designed to attack any living creatures with mutated DNA. With all genetic impurities removed, the Enclave (who remain protected from radiation) could take over. The player frees both his fellow villagers from Arroyo and the Vault 13 dwellers from Enclave control and subsequently destroys the Enclave's oil rig, killing the Enclave and United States President Richardson as well as a genetically-modified secret service enforcer known as Frank Horrigan (the game's creators described him as "a munchkin's worst nightmare: a super mutant in power armor").[citation needed] In the end, the inhabitants of Vault 13 and the Arroyo villagers create a new prosperous community with the help of the GECK.