Around 2198, a Reaver delegate comes to the Eastern Brotherhood of Steel Bunker Delta, bringing news that a large Calculator's robot force has all but annihilated the main Reaver camp in Newton. The Reavers' numbers were devastated by relentless attacks and they would soon be destroyed. Normally, the Brotherhood would gladly allow one enemy to destroy another, but the Reavers have something to offer - an EMP device that has a devastating effect on electronics, making it an effective weapon against the robots.
The game takes place in 2197 in the American Midwest. The Eastern Brotherhood of Steel is trying to claim territory surrounding Chicago. The Warrior, the player character, is a new recruit to the Brotherhood, tasked to lead a squad of soldiers made up of available initiates.