It is 1914. As the Great War looms, the mighty Ottoman Empire is crumbling. Constantinople, the once vibrant, multicultural capital on the shores of the Bosporus, is about to be consumed by chaos. Michael Boghosian (Oscar Isaac), arrives in the cosmopolitan hub as a medical student determined to bring modern medicine back to Siroun, his ancestral village in Southern Turkey where Turkish Muslims and Armenian Christians have lived side by side for centuries.

Photo-journalist Chris Myers (Christian Bale), has come here only partly to cover geo-politics. He is mesmerized by his love for Ana (Charlotte le Bon), an Armenian artist he has accompanied from Paris after the sudden death of her father. When Michael meets Ana, their shared Armenian heritage sparks an attraction that explodes into a romantic rivalry between the two men. As the Turks form an alliance with Germany and the Empire turns violently against its own ethnic minorities, their conflicting passions must be deferred while they join forces to survive even as events threaten to overwhelm them.

The one promise that must be kept is to live on and tell the story.