A condemned kettle is Owen Voss's last chance to earn a living. Once a heat assessor, now suspended and nearly broke, Owen buys a crate of discarded enchanted appliances to repair and sell. His first kettle works. Then a test makes the laundry's return line turn cold, and refunding his customer costs him almost everything he has earned. The appliance's hidden construction points toward a supply the city's heat company has never properly explained. The company offers money to recover his stock and settle the dispute. Owen needs that money. He also needs to know who has been paying for the warmth reaching Greybridge's new northern homes. With laundry owner Mara Bell, he starts building an independent recovery business from the heat a rolling mill throws away. A factory stoppage can end their supply while the equipment loan still needs paying. When the river freezes and the city's delayed furnace cannot arrive, tracing the hidden supply becomes urgent. Stopping it without a lawful replacement could leave more rooms cold. Owen has to earn back his colleagues' trust and help keep people warm while the source is exposed.