Tuppence's curiosity about a cryptic message in a newspaper personal column leads her to suspect a romantic rendezvous. Attempting to prove her theory correct she persuades Tommy to attend the Three Arts Ball and later to visit a cafe suspected to be a meeting point. Hearing a cry from an adjoining room, Tuppence investigates and discovers Lady Merivale. Before dying Lady Merivale whispers ""Bingo did it"" Captain Bingo Hale, Lady Merivale's lover, is arrested, which leads the Beresford's to go from accusers to trying to prove Captain Hale's innocence.