context: In 1821, Napoleon Bonaparte (Holm), after six years in exile on the isle of St. Helena, has a plan to escape. Switching places with lowly French deckhand Eugene Lenormand (Holm again), Napoleon will make his way to Paris, at which time Eugene will announce the switch, allowing Napoleon to reclaim his throne.
  However, the plan quickly goes awry: the ship Napoleon is serving on abruptly changes its itinerary and docks in Belgium instead of France. Having to make his way to France by land (and gaining an appalling look at the tourist trap the Battlefield of Waterloo has become), he is finally met at the French border by a loyal agent, Sgt. Bommell (Clive Russell), formerly of the French Imperial Guard. Bommell gives him the name of another agent in Paris he can trust, Lt. Truchaut.
  Arriving in Paris, Napoleon is surprised to find that Truchaut has recently died. Passing himself off as an old comrade of the Lieutenant, Napoleon accepts the hospitality of Truchaut's widow, Nicole, whom everyone calls "Pumpkin" (Hjejle), and makes the acquaintance of her other lodger, Dr. Lambert (McInnerny) and her adopted young son, Gerard.
  The crucial flaw in the plan reveals itself when, back on St. Helena, Eugene decides he likes living in the relative luxury of Napoleon's exile, and refuses to reveal the switch. Napoleon's French entourage find themselves unexpectedly powerless, as Eugene stuffs his face with sweets, dictates his own bawdy version of Napoleon's official memoirs, and even manages to convince his British captors that he is the true Napoleon.
  With no news from St. Helena, Napoleon is drawn into Pumpkin's life. When her fruit-selling business is on the brink of failure, he applies his own talents for planning and organization, and the business becomes prosperous again.
  As affection develops between Napoleon and Pumpkin, Dr. Lambert, who had designs on Pumpkin himself, jealously searches for some kind of dirt on "Eugene." Going through his bedroom, Lambert is shocked to find a small cameo portrait of Napoleon's young son, and realizes who "Eugene" really is.
  On St. Helena, Eugene abruptly drops dead of some kind of stomach complaint (in real-life, Napoleon reportedly died of gastric cancer). Quickly realizing that the dead man on the island is not Napoleon, the British garrison commander lays out their options: either they announce the fraud, and commit themselves to heinous punishment, or else they maintain that "what we have here is a dead emperor" and so everything is well.
  When "Napoleon's" death is announced throughout France, the real Napoleon abruptly remembers his original plan and announces to Pumpkin that it is time for him to take his rightful place on the French throne. To his fury, Pumpkin is horrified and dismisses him as a delusional lunatic, pleading with him that she loves Eugene, and hates Napoleon.
  With no loyalist agent in Paris to vouch for his identity, Napoleon finds himself an Emperor without an army, or a friend. He is reduced to going to Dr. Lambert, who he realizes stole the portrait, and demanding it back. When he demands to be told "who I am," Lambert retorts, "I will show you."
  In revenge for being beaten to Pumpkin's affections, Lambert lures Napoleon onto the grounds of a sanitorium, where it seems every patient is dressed up as Napoleon, and pretending to be him. Lambert withdraws, expecting the real Napoleon to be rounded up by the attendants, but a shaken Napoleon escapes the grounds by climbing over the wall, suffering a nasty cut on his hand from the chevaux de frise on top. Lambert drops the cameo down a sewer grate.
  Emotionally and physically exhausted, Napoleon returns home to Pumpkin's house. She lovingly tends his wounds, and whispers in his ear, "you are my Napoleon."
  While Gerard is looking at a pictorial account of Napoleon's life on a magic lantern, Napoleon tells him the story of what really happened. It seems that Gerard, if no one else, believes Napoleon's story.
  Deciding that he is happiest living a simple life with Pumpkin, Napoleon destroys all his mementos of his former life, except his old Imperial Guard uniform, which he leaves at the local military post as a gift for Sgt. Bommell, with a message that "Eugene Lenormand has moved on."
  An after-note states that Napoleon Bonaparte lived out the rest of his life in Paris and was buried next to Pumpkin; while Eugene Lenormand's body was brought back to Paris and interred with high honors in Les Invalides.
question: Who tries to turn the imposter in?
answer: One of Napoleon's loyalists on the island tries to turn the imposter in.