In 18th-century France, Baron Grégoire Ponceludon de Malavoy, a young and penniless aristocrat and engineer, devises a scheme to drain the marshy region of the Dombes that is causing disease. He sets off for Versailles to seek the support of King Louis XVI, but finds himself in a world of corruption and callousness among the aristocracy, including Madame de Blayac, who cheats at games with her lover L'abbé de Vilecourt. Ponceludon's own wit and determination are put to the test as he navigates the treacherous waters of court politics, all while trying to win the heart of Mathilde de Bellegarde, the doctor's daughter. Ultimately, Ponceludon finds solace in his work and a chance at true love with Mathilde.