It is 1895, and turn-of-the-century Paris is as chaotic as it is glamorous. Industry and invention have created ever greater wealth and terrible poverty. One autumn morning, an anarchist boards the Granville to Paris express train, determined to make her mark on history.

Aboard the train are others from across the globe: the railway crew who have built a life together away from their wives, a little boy travelling alone for the first time, an artist far from home, a wealthy statesman and his invalid wife, and a young woman with a secret hidden under her dress.

All their fates are bound together as the train speeds towards the City of Light .