Mankind's fate resides in the past

Everything that separates humanity from the common animal has disappeared in the blink of an eye.

Title, name, status... Nothing is left. Order is nonexistent. Law has been reduced to vigilante justice. The fate of mankind rest in the hands of a thumbless beggar who never had a name to begin with. He knows of an ancient castle that could hold the key to restoring peace. But is that what he wants?