In the summer of 1960, in a remote region of Patagonia, a German doctor (Alex Brendemühl) encounters an Argentine family and joins them on a caravan journey across the desert. The family rekindles his obsession with purity and perfection, particularly Lilith, a girl on the threshold of adolescence whose body is unnervingly small for her age. The fascination is mutual. Lilith, in the midst of awakening sexuality, feels a disturbing attraction to the stranger. When they arrive in Bariloche, Enzo (Diego Peretti) and Eva (Natalia Oreiro) welcome him as the first guest at their lakeside inn on Nahuel Huapi, unaware of his true identity. Despite initial distrust, the stranger gradually captivates them with his manners, elegance, scientific skill, and wealth.