Another in the Roy Grace series by Peter James.
In this installment, Detective Superintendent Roy Grace continues his work solving complex cases in Brighton, England. The plot revolves around a mysterious and dangerous online dating agency that appears to match couples based on their compatibility at first sight. However, as the story unfolds, Grace discovers a dark and deadly side to this seemingly innocent service.
Besides cleaning up this case, he also winds down a former problem and moves on to new adventures in London.