Thomas Pitt is now in charge of Special Branch and finds himself in a strange world where loyalties and obligations are rarely spoken about but affect all his dealings with everyone. When a ladies' maid disappears from the house of Dudley Kynaston the case becomes one for Pitt because Kynaston is working on designs for submarines to be used in warfare.
The maid's disappearance could be a matter of national security. Pitt needs to use all his contacts and those of his wife, Charlotte, to solve the case and prevent damage to his country's interests. I enjoyed this well written Victorian crime novel with its meticulously researched background. It is the first book I have read by this author and I shall definitely be reading more of this series.
The only reason why I have not given it five stars is that I felt I was missing a dimension of the story because I hadn't read the rest of the books in the series. Yes it can be read as a standalone novel but I think the reader will probably get more out of it when they are familiar with the rest of the series. The relationships between the various characters will mean more and nuances in the dialogue and interactions will be clearer.
If you like Victorian crime novels then try this series for interesting mysteries and believable and three dimensional characters as well as a vivid evocation of late Victorian London.