Agatha Christie 
King of Clubs 

Prince Paul of Maurania hires Hercule Poirot to prove that his fiancee, the famous dancer Valerie Saintclair, was not involved in the murder of Henry Reedburn. She was the last to see the unpleasant businessman alive, and after an argument with him, she ran off to the Oglander family home. Poirot and Hasting will investigate the case until they discover a very old secret.