I Am a Thief (1934)

Well-done, fast-paced, slick, and fun mystery story about a pack of jewel thieves and assorted other characters aboard the Orient Express, all in hot pursuit of the famous "Karenina Diamonds". In Paris, the insurance companies are upset about the glut of jewel robberies happening in the city lately, so put up for auction the exquisite Karenina diamond necklace in hopes of luring out the thieves from hiding. Dealer Ricardo Cortez bids and wins the diamonds and is soon traveling by train to Istanbul with many others chasing him and, more importantly, chasing the prized jewels including smartly-dressed Mary Astor, a lady of mystery.

Most of this film takes place aboard the train, in state rooms and dining car, with plot twists and turns that remind me of an early Hitchcock film. It also reminds me of an Agatha Christie style mystery story including gathering of all characters in the dining car for interrogation by smart police detective. This movie does not disappoint - with top-notch acting all-around and an interesting, suspenseful plot, this is really an excellent film.