Rusted Oath

A Class-4 heart engine is not supposed to glow amber. It is not supposed to spit aether at all once it is clamped into its iron cradle, mounted in a surgeon's geometry, and declared stable. But in Sera Voss's repair shop, the light bleeds wrong through the window in slow, pulsing veins, and broken glass scatters across the floor like a warning no one asked for. Sera works with her back to the door, elbows deep in a machine that has quietly betrayed every guarantee its maker swore to her , and to the city that runs on engines like it. Her assistant Sprocket hovers at the threshold, watching the glow that has no right to exist. Behind them both waits a wider world of contracts and oaths: Cassius Wren, whose name is on too many of those guarantees; Yuki Tanaka and Maren Doss, who know what stable engines cost when they are not; Tobiah Fell and Lysandra Moreau, whose debts are older than the shop; and Darrell, who remembers what the first heart engines took to light. A rusted oath is still an oath. It still binds. When Sera finally steps back from the cradle, she holds a choice no mechanic should have to make , repair what is breaking, or let it fail on purpose , and every name on her ledger is watching to see which one she chooses.