After the canonical events of Fallout 3, The Lone Wanderer, Monroe, attempts to settle down in his home in Megaton. After being newly elected as mayor, aiding Sherrif Lucas Simms, he realizes relaxation may not be an option. Several problems soon arise with a surge of travelers coming from Richmond, seeking shelter in Megaton, to disagreements with the Brotherhood of Steel DC chapter. Monroe and his companions Elliott, Fawkes, Moira, and his trusty Dogmeat must work together to tackle the responsibilities put on their shoulders to avoid the destruction of everything they've built. But not everyone in the wasteland supports their endeavors and makes it well known.