Marion Lane and the Midnight Murder

Marion Lane and the Midnight Murder is a 2020 mystery by T. A. Willberg and the first book about a secret detective agency in London. Miss Brickett's Investigations & Inquiries works from tunnels beneath the city streets and is staffed by recruits trained to use their own devices and their own judgement on cases the police have given up.

The murder of a filing assistant in April 1958 sets the plot in motion. The woman had been sent an anonymous note naming a time and a place, and because she died in a room nobody else could reach, the culprit has to be a colleague, which turns the agency's own hierarchy into the list of suspects. Marion, a first-year trainee, is drawn into a search for a killer among the people who are supposed to be teaching her the work. The note named a time and a place, and because the room she died in could not be reached by anyone outside the agency, the culprit has to be one of her colleagues.

The book establishes its own version of post-war London, with the tunnels and the agency's rules standing in for police procedure, and it closes its case while leaving the institution and its trainees in place.