1982. French President François Mitterrand decides to launch an international architectural competition for the flagship project of his mandate: the Great Arch of La Défense, aligned with the Louvre and the Arc de Triomphe. Against all odds, Otto von Spreckelsen, a Danish architect, wins the competition. Overnight, this 53-year-old man, unknown in France, arrives in Paris where he is propelled at the helm of this pharaonic project. While the architect intends to build the Great Arch exactly as he envisioned, his ideas quickly clash with realistic constraints and the vicissitudes of politics.