It is really starting to feel like these books are becoming trapped in the concept. For the first few books, it seemed like the strange old photographs sparked the construction of an unusual world. By this fourth book, it feels like they are largely driving the plot and are the only real original ideas left. It is the experience of reading and hmm, so why are they talking to a mermaid? Then a few pages later, oh ok, he had a photograph of somebody dressed up like a mermaid. Why are they in New York now, oh, because he found some old postcards of New York.

As the universe in this series starts to expand, the concepts and the characters are getting stretched too thin. This book seems to be the start of a second trilogy and was a bit of an uninspiring slog to get through, I feel like I can give up on this series and move on with my life.