The alarms began at the fifteenth hour of Hearth’s day, in the forge under the old heart.
They had gone up to Hearth’s service level at noon, the crew, to prepare the return-channel trial. A trial, short of the full pulse: the certified test channel with its second mirror iron sample, fitted to Hearth’s old heart through a temporary port in the heart’s housing, with a copper radiator on the outside, to see whether a seventh channel at Hearth’s scale would take a pulse the way the scrap-cell rig had. Tavin had wanted a week to prepare it. They had a day. The joint custody terms were signed; the routes would open; but the lattice was building pressure behind the command well, and every day the chain of returns did not start was a day the old heart carried the strain alone.
The forge at Hearth was not the yard. It was a long chamber at the top of the service stair, beyond the shrine’s gate, where the old heart sat in its housing: a great dark sphere of seam iron the size of a house, banded and riveted, with the brace’s six segments ringed around its middle like a belt. The cradle stood at its side. Tavin’s chalk mark was still on the frame: 90. And beside the cradle, on the left, a plain wooden chair that Brisk had carried up the service stair that morning on Sera’s orders, set facing in.
