The year is 1751 and at the age of twenty Tristan Hart leaves home to study medicine at the hospital of St. Thomas in London. Mr. Hart is also a psychotic. He is obsessed with the nature of pain and medically preventing it, but his equally storng and much harder to control obsession is with causing it. Desperate to understand his deviant desires, he uses the new tools of the age--reason and science and skepticism--to plumb the depths of his own kard mind.