Scroll down for the solution to the astronomy puzzle.
It becomes quite evident that Xela does not live on Earth. Rather, invert on the Earth’s sky. Then stars in the night sky map to cities on Earth and vice versa. Mapping a brighter star to a larger city, and noting whether population growth seems to be waxing/blueshifting or waning/redshifting, we figure that we should find a location in our night sky where three very bright blue stars occur in a row. Xela lives in Alnilam, Orion.