Shortly after World War I, veteran Raphaël returns home from the frontlines to find himself a widower, and father to an infant daughter. Raised by her father in rural Normandy, the child Juliette grows into a lonely young woman who dreams of greater possibilities. She seeks refuge in the nearby woods, where she meets a witch who promises scarlet sails will one day take her away from her village. Reckoning with her future and swept away by a rakish young pilot who literally falls from the sky, Juliette never stops believing in the witch's prophecy. Tracing Juliette's journey throughout the twenty years of great invention between the world wars, the film delicately weaves together music and fantasy, history and folklore, realist drama and ethereal romance, to craft a timeless story of a young woman's emancipation.