James (Jimmy) Caplon Answell. A pleasant, wealthy young man about to be married, who stands accused of murdering his future father-in-law.
Mary Hume. His fiancée.
Avory Hume. Her father, a bank director and archery enthusiast.
Dr. Spencer Hume. Avory Hume’s brother, a physician.
Amelia Jordan. Avory Hume’s confidential secretary and housekeeper.
Captain Reginald Answell. Jimmy Answell’s brother.
Herbert William Dyer. Avory Hume’s butler.
Randolph Fleming. Hume’s neighbor and fellow archery enthusiast.
Detective-Inspector Mottram. The investigating Scotland Yard officer.
Sir Henry Merrivale. Known to all as H.M.
Ken Blake. His assistant.
Evelyn Blake. Ken’s wife.
Lollypop. H.M.’s secretary.
Dr. Tregannon. A mental specialist.
Dr. Peter Quigley. Tregannon’s assistant.
George Joseph Shanks. The odd jobs man.
Horace Carlyle Grabell. A truculent cleaning specialist.
William Rath Cochrane. Manager of the Left-Luggage Department at Paddington Station.
Plus assorted police officers, counsels for the Crown, and officers of the court.