A Canadian commercial pilot sees a telecast in London of an interview with Sir Mark Lodden at his home. The Canadian is convinced that the baronet is a fraud, that he is actually a look-alike actor named Frank Welney. The Canadian, the baronet, and the actor were all prisoners in the same German camp during the war and escaped together. One of them disappeared during the escape. Was he Sir Mark or Welney? The tabloids have a field day with the Canadian’s accusations and Lady Maggie urges her husband to sue for libel and engage the distinguished barrister Sir Wilfred. The long-drawn-out case is made complex by the fact that Sir Mark himself is not quite sure of his identity. Injured in the war, he stutters on occasion and has difficulty remembering portions of his life. As the evidence sways back and forth in court, it begins to appear that Sir Mark is an impostor and the possible murderer of the missing baronet. Even his wife is convinced of his guilt and turns against him. She denounces him as a stranger who stole her love.