S2, E10: Poirot's compatriot, famous film star Marie Marvelle, shows him letters demanding the return of her magnificent diamond the 'Western Star'. Despite Poirot's protests, Marie is determined to keep hold of the diamond so that she can wear it at a weekend house party at Yardley Chase. Lady Yardley owns the companion jewel, the 'Eastern Star' and Marie is determined not to be outshone. Before the glittering occasion can take place, both diamonds are stolen.