Millionaire Lord Charlton has altered his will in favor of his nephew, Simon Warwick, who had been adopted by American parents when his own were killed in World War II. But when Lord Charlton dies,two men claiming they are Warwick turn up in London too claim the estate. Then one is found dead, and Chief Superiendent Henry Tibbett is faced with a double mystery: Who is the murderer, and who is Simon Warwick?

Henry Tibbett, Chief Superintndent of Scotland Yard has for years delighted those who love a classic British detective story. A modest, self-effacing man, Tibbett possesses an almost uncanny "nose" for crime, and those who know him well realize that his gentlemanly demeanor masks a shrewd mind and a fearless spirit. When he teams up with his wife, Emmy, a cheerful but formidable woman, there isn't a criminal anywhere who can rest secure.