Early 2000s. A notary in Milan is tasked by a Swiss bank to locate the heirs of Giovanni Janowitz. In Florence, Nathan Giannotti discovers not only that his family changed its surname during World War II, but also that his grandfather had opened a safety deposit box in Switzerland before being deported and dying at Auschwitz.

Inside, Nathan finds only a receipt dated “Florence, 1938”: it documents THE EXCHANGE between a painting by Canaletto and one by Otto Dix, but more importantly, the document testifies to a Nazi-era forced sale.

With the support of two Florentine professionals, Lorenzo and Valentina, Nathan embarks on an impossible quest to track down the lost masterpiece. The investigation unfolds across stunning locations: from the Kunsthistorisches Institut to the archives of the Florence Export Office; from the Jeu de Paume (with Rose Valland’s precious registers) to the ERR Project in Paris; from the Collecting Point archives in Munich to the BAVD in Berlin.

Gradually, the story of an elderly, unknown man emerges someone whose existence suddenly comes to light in 2012, after decades of impenetrable obscurity. Two narrative lines inevitably converge. Two destinies, two eras, one truth.