We've found some old recordings and intercepted eyebot transmissions that the scribes say could indicate an Enclave presence in Chicago. It might just be that somebody left the radio on. Or it might be a small outpost that was abandoned by the main forces.

...Or it might be an army.

[Anthony's expression is grim. The Brotherhood's military capabilities have expanded by leaps and bounds over the last decade, incorporating Enclave gear into their own, like the vertibirds, reconstructing massive war vessels like the Prydwen and Liberty Prime. If there's another war between the Brotherhood and the Enclave, it may look a lot like a pre-War kind of war. And everyone knows where that ended.]