"I am simply Hercule Poirot, but in my own way, I am great..."

Hercule Poirot boards the Blue Train to the French Riviera. The same train taken by Ruth Kettering, the pampered American heiress leaving behind an unhappy marriage and the dreary English winter for a lover waiting for her in France.

However, at dawn, Ruth is found dead, strangled in her compartment. And the Heart of Flame, the famous ruby she had with her, is nowhere to be found... Hercule Poirot once again employs his detective genius to solve a mystery that has it all: immense wealth, charming men, fatal women, hidden passions, and unspoken secrets...