Napoleon's return
In a charming fantasia on how the last years of Napoleon's life might have gone, The Emperor's New Clothes—an adaptation of Simon Leys's novella The Death of Napoleon—features a Bonaparte who plots a daring escape from St. Helena. He plants a double, a sailor named Eugene Lenormand, in his place while he steals back to Paris to reclaim his power. Both figures are played with brio by Ian Holm.
There's a small but distinguished strain of movies about the doubling of men in power—Rossellini's General Della Rovere and Kurosawa's Kagemusha come to mind. (Dave, about a man who stands in for the U.S. president, is less distinguished.) But they tend to focus on the way in which the performance transforms the commoner—how he stretches himself to fill the role, acquires greatness, first by chance and circumstance and then by earning it. The Emperor's New Clothes flips this pattern: it's mostly concerned with the metamorphosis of Napoleon; Eugene is merely an ingenious and hilarious comic device.
Napoleon's plan is frustrated by the death of his main contact in Paris and by Eugene's willful refusal to admit, at the arranged time, that he's a fake; he finds the life of a famous conqueror in exile, stuffing his face and dictating his alleged memoirs, far more agreeable than that of a paltry deckhand. So Napoleon, stuck in limbo, is forced to adapt to the life of an anonymous middle-class Parisian.