The all-powerful Guild of Private Detectives take an instant dislike to the new Inspector Blake because of his ban on the use of Private Detectives at Scotland Yard. But when the Chairman of the Guild turns up dead, Blake finds himself working alongside Eliza whether he likes it or not. Meanwhile, Ivy takes on a new opportunity, but what will the consequences be for her engagement to Mr. Potts?

Eliza's life is turned upside down when she finds herself dragged into a missing persons case with a recently released convict by the name of Patrick Nash.