"Yeah," Tony said shortly, a distracted half of a syllable like he wasn't entirely engaged with her, like he wasn't just asking her to work from the opposite end as he instructed, "Keep going back. Every time there's a population change, make a note." There had to be paperwork, the boring, accounting kind, detailing the bricks bought and glass blown to build a city. Eventually, Tony would hit the dark spot, the big black hole that Enide wasn't supposed to tell him about.