Valhentin Rochefort, professional duellist and down-at-heels aristocrat, arranges the assassination of Henri IV, King of France. Fleeing from the consequences, he makes for England, on the way picking up two companions - a young boy, Dariole, also a duellist, with whom Rochefort is sexually obsessed; and a ship-wrecked 'demon'. As the complex story unfolds, Rochefort's dreams of the future grow increasingly stranger and more contradictory. He realises he must act - but, how? What is the right choice? And how much of the future will depend on what he does?