Zarachius Skie is presumed dead. His mentor, the Arcanist Mordekai Gethsemane, had been arrested for conspiracy to commit regicide. Zarachius knew it was false. He did what had to, and snuck onto a military train to break Mordekai out. But now, the Ancien Legion, vengeful anarchists, and Mordekai's old co-conspirators are doing whatever it takes to bring Zarachius out of hiding. They need to know what he knows. They need to know the secret he uncovered on that train.