In six days Max Silverskin, thief and trickster, must discover the secrets of his heritage or perish from the witch mark - the silverheart - on his chest which will devour his heart. Lady Rose Iron, leader of the mighty Clan Iron in Karadur, city of metal, steam and ancient secrets, is thrown into an uneasy alliance with Max as she searches out the secrets which will save the city's future. Captain Cornelius Coffin, head of the clans' security forces, is in love with Lady Rose and obsessed with capturing Max. And there are others, in Shriltasi, Karadur's underworld twin, who know the prophecy which says that only Max Silverskin can save both realms.