Saint-Yves, a cloak-and-dagger film, filled with action and humor, is taken from a novel of the same name by Stevenson. Saint-Yves, a young officer in the Napoleonic army, falls prisoner to the British. Exiled to Scotland, he finds the love of his life in Flora. But he must also face terrible adversity, in the shape of his brother Alain, whom he thought had died in the Terror.