In the heart of Paris, an entire palace has disappeared. It was the very first residence of the kings of France. Long before Versailles, long before the Louvre, the Palais de la Cité stood on the most prestigious island in Paris, the historic cradle of France, opposite Notre-Dame. So majestic in the Middle Ages, this palace has become a ghost of history. Over the centuries, this architectural masterpiece has almost completely disappeared. A trio of experts will bring it back to life in 3D. Using science and unprecedented excavations, they will track down the pieces of the puzzle to reconstitute it at its peak in the 14th century, and bring back to life the people who inhabited it. From the Romans to the Vikings, from Saint-Louis to the accursed kings, all have left clues to this "Versailles of the Middle Ages".