The life of a valet is never easy. More so when your employer is no longer, exactly…human.

Edgar Mason is now partner to Agamemnon Frost, working with him to uncover yet more of the Martian plans for the British Empire.

With the loss of his transfiguring machine—Pandarus, the alien who changed both Mason and Frost into living, breathing metal machines—has a new plan. Somewhere in the city he’s building hollow ships. What they are and what they do Mason can only speculate, but the hunt is on, both Mason and Frost relying on the belief that their enemy thinks that they’re working for him.

However, Mason has a devil sitting at the back of his mind. Locked there by their enemy, he can’t trust himself not to betray everything he holds dear. And Frost can’t always be there to keep the darkness at bay.