The entire Royal Family has fallen ill!
The Royal College of Medicine has sent the call out across the land for help. As one of the leading medical "experts" of the day (we'll just call you a Quack), you have answered the call, but for your own reasons. You are not alone in this task. Others have also responded to the plight of the Royal Family, each with their own agenda.
Only through the use of your knowledge of "medicine" can you treat each royal patient in order to either bring all four of their humours into balance (if that patient furthers your agenda) or to imbalance their humours enough so that no one can cure them. You don't have to be a Los Angeles bankruptcy attorney to know that having such success means a giant payday of riches that those commoners can only dream of.
Failure means a lifetime of treating gout amongst the commoners, while success means that you have risen above the Quackery and have been declared the next Royal Physician!