A seventeenth-century portrait hanging in Venice shows a man in full samurai armor, and the film follows historians and art experts trying to explain why. The trail leads back to Hasekura Tsunenaga, a Japanese emissary sent across the world by a feudal lord to open relations with Rome, whose delegation passed through Venice on its way to and from the Vatican. Paintings, church records, and period accounts get pulled together to reconstruct a diplomatic mission that most people have never heard of, one that briefly connected a samurai retinue with the doges and cardinals of Baroque Europe. The film treats the portrait itself as evidence, reading the details of the armor and the sitter's pose against what is known of Hasekura's actual journey. It is a compact piece of detective work built on a single striking image, showing how a scrap of art history can reopen a forgotten chapter of early contact between Japan and Europe.