Disgraced Civil War surgeon, Dr. Alexander Potter, now con artist and snake-oil seller, travels the wet roads of the Pacific Northwest with a disheartened company of strongmen, illusionists, fortunetellers and musical whores. Under their mysterious and murderous leader they entertain the masses while peddling the Chock-a-saw Sagwa Tonic, a vital elixir touted to cure all ills both physical and spiritual.