In a dry canyon in northwest New Mexico, more than a hundred stone buildings sit on top of boulders, walls hand-laid around the curve of the rock, with no way in except a climb. For most of a century, archaeologists agreed on exactly who built them and why — a tidy explanation with a date, a cause, and a place in every textbook. Then a researcher at a tree-ring lab in Arizona started pulling samples from the roof beams one at a time, asking a question nobody had thought to ask, and the answer didn't line up with the story at all. What that wood revealed about the Navajo homeland of Dinétah reopened a question that was never really about archaeology in the first place.