Agatha Christie 
Mystery of the Blue Train [EPUB ebook] 

In this classic mystery by the Queen of Crime, Hercule Poirot boards a night train bound for the French Riviera . . . and murder. American heiress Ruth Kettering needs to get away from it all. She’s left her unhappy marriage behind her and booked a ticket on the luxurious Blue Train, heading to the French Riviera where her lover is waiting. But when the train arrives in Nice, Ruth is found dead in her cabin, and her priceless ruby is missing. Although the evidence points to Ruth’s estranged husband as the prime suspect, Hercule Poirot is not so sure. Now, to make sense of this perplexing puzzle, there’s only one thing the great Belgian detective can do: recreate the murder. Originally published in 1928.