By the looks of it, it'll be in and around Boston. Probably going to see The Commonwealth for the first time in the series. By the looks of the trailer I'm going to guess that it'll start just at the outbreak of the Great War with the PC (being a child) getting into a Vault, being locked in til adulthood (I'm gonna guess either 10, 20, or 25 year mandatory lockdown) then sent out on a recon.
Super chuffed for this.