Explorers have discovered a clue that brings them to the origins of mankind on Earth. This leads them on a journey that takes them to the darkest corners of the universe.

During a horse drive to Wyoming, a man and his estranged nephew meet a man transporting five Chinese girls to a brothel; the next morning he is gone with the drovers' money, leaving the girls behind. The intended buyer sends a hired gun out to retrieve her property, as the cowboys try to keep the girls safe, and deliver the herd of horses.