Diego Amador is a young physician and recent immigrant to London from the Andalusia region of Spain. After struggling to get his independent practice going, Diego is hired by a rich philanderer as his personal doctor, to accompany him as he travels the world for his business. On these travels, Diego is introduced to the seamy parts of each city he visits while seeking out native customs and cures. He soon discovers an elixir which will help him win the affections of the girl of his dreams, but the trade-off comes at a great cost to his soul.