A Russian refugee who masquerades as Zara, niece of Francis Markrute, comes to his home and marries Lord Tancred, a scion of the English nobility, after a long series of misadventures she makes a full confession to her supposed uncle and to her husband regarding her origin and her young son by a former marriage to a Russian prefect of police, whom an infuriated mob murdered for his cruelty. Tancred is stunned, but only for a moment. Overwhelmed with forgiveness he avows his undying love.