Patagonia, 1960. A German physician meets an Argentinean family on the long desert road to Bariloche where Eva, Enzo and their three children intend to open a lodging house. This ideal family reawakens his obsession with purity and perfection. Unaware of his true identity, they accept him as their first guest, gradually won over by his elegant manners, his scientific knowledge, his charisma and his money - until they discover they are living with one of the biggest war criminals of our times.