Hall of Mirrors: Bryant and May, Book 15

In 1969, ten guests gather at Tavistock Hall for a weekend that quickly turns suspenseful. Among them are detectives Arthur Bryant and John May, who are undercover to protect Monty Hatton-Jones, a whistle-blower in a high-stakes bribery trial. As tensions rise, the house's owner plans to sell the estate to a secretive millionaire, but the situation escalates when the millionaire mysteriously vanishes, leading to a chilling murder mystery.