This is not the England we know. Victoria has ascended the throne - several times, in various new bodies. It is a time of gas lamps and regularly scheduled airship flights, of trams and steam driven clockwork with countless smoke belching stacks. In filthy, crowded, fast growing London, the capital of the Empire of the Lion, a series of shocking murders threatens the throne itself.

Jack Straker, Lord Templeton, the energetic young inventor and Dread Agent for the Crown, believes he has created a weapon to defend the Prince Regent: a reanimated, clockwork enhanced corpse he can control. But members of the Ancient Order of the Tentacles have other plans for the "Iron Assassin."

Together with his friend, Mr. Bleys Hardcastle, and the recently recruited Dread Agent Rose Gordhammond, Lady Harminster, Jack must outwit the Ancient Order and regain control of his invention before they can assassinate the Prince Regent.