The full forging began with slow heat, in the hour before Lorn’s local dawn, with the old heart still hanging in its rings across the drum and the new one lying in pieces on the platform beneath it.
Orison had opened the forging fixture for her the night before, after the wheel. It was a frame on the drum’s central platform, directly under the old heart, where the replacement would be built: a ring of pale alloy clamps that could hold the heart’s parts in place while they were worked, and below them, set into the platform’s floor, the forge’s furnace. There was no fire in it, only a plate of dark metal that grew hot when Orison opened its feed, drawing heat from the lamp’s own reserve, and threw that heat up evenly into whatever lay in the fixture above it.
“The furnace,” Orison said, “has four stages. I believe it has four. I have a record of four.”
“Then we use four,” Mara said.
She brought it up in stages. The first stage was barely warm, a heat she could hold her bare palm above without discomfort. She laid the root iron in the fixture’s center: the dense dark mass of it, Sera’s harvest and her own, the core of the heart. She let it sit in the first stage’s heat until its deep note in the graft warmed and softened and came up round.
