As a writer of original works, Massie's "Tudors" projects presented her with some unique challenges.
Massie, 56, was sent scripts for each episode and then wrote the season into one book at the same time it was being filmed in Ireland.
The books had to be loyal to the show, but the scripts, as they tend to be, were scant in details and description.
So Massie had to conduct historical research to bring the story alive on the page.
"The script would say something like, 'King Henry enters the room. He sits on a chair. He starts to talk,'" she said. "I had to fill in details of the way things looked, what they ate, how long did it take to get from London to Hever Castle (by horse and carriage). Things like that."