For the most part this novel is the story of a young woman, whose desire to gain more knowledge compels her to dress up as a man, who (due to events beyond her control) eventually rises to become the pope.

When he discovers that Joan has learned to read, her father calls her “child of the devil” and blames the illness and death of his oldest son, Matthew, on her as a punishment.

Although he remains faithful to his wife, she resents Joan and seizes an opportunity to force her into marriage at age 14.

After her convalescence she goes to Rome, where she becomes the personal physician to the Pope, Sergius, a weak man easily led by his venal brother Benedict.

When the Frankish Emperor Lothar marches on Rome, Benedict flees with funds intended to try to placate him, and Joan is restored to her former place of authority.

Anastasius plans to seize the throne and realises he needs to remove Gerold before he can attack Joan directly.

He gained revenge of a sort by obliterating Joan from history, excluding her from his book on the lives of the Popes.