The saltpeter smell reached him before the billet came into view. A sharp mineral note in the winter air, distinct enough to know what it was before the source appeared.
Batu followed it east through the camp.
Wei was outside when he arrived, standing at the billet's entry with his arms folded against the cold. A compact man past forty, with the careful eyes of someone who had spent his working life measuring small differences.
His assistant was at the supply frame behind him, unwrapping ceramic containers from oilcloth.
They introduced themselves. Wei's Mongolian was functional and direct.
"The proposal was a spring meeting at Samarkand," Batu said. "What changed."
Wei looked at him without apology. "The Ayas relay. Merchants carry better information than official couriers."
He paused.
