The two are unusual criminals in the pocket of a gang Lord named Will Twentyman, the Grave Eorl of Southwark. Mariner is the best cutpurse around, a strange Calvinist girl who dresses like a boy and is partner in crime to Kit Skevy, Southwark's best brawler who carries a secret: he cannot feel pain. When caught out in their unfortunate larceny, Kit is kidnapped by the threatening alchemist Lord Isherwood (a man who will stop at nothing to achieve his hopes for the Red Lion elixir) and his studious son, Lazarus Isherwood, with whom Kit develops a complicated intrigue. When Mariner enlists the help of a competing French alchemist, Lady Elody Blackwater, Mariner and Kit are thrust into the shadowed, political world of Tudor alchemy.
