A stranger arrives in a remote mountain village carrying a backpack containing a notebook and eleven gold bars. His mission is to discover whether human beings are essentially good or evil. The stranger puts a proposition to Chantal Prym, his first acquaintance in the village, and with it gives her the power to prove or disprove a supposition that has tormented him for years--given the right set of circumstances every human being on this earth would be willing to commit evil.