The source material is primarily an excerpt from the BBC Books novel Doctor Who: The King’s Dragon by Una McCormack, which details an adventure where the Doctor, Amy, and Rory encounter a technologically advanced, mind-controlling metal called "Enamour" and a large golden dragon on the seemingly peaceful planet Geath. This narrative features a local political struggle and an ancient interplanetary civil war involving two powerful alien factions, the Herald (representing the exiled Bright Nobles) and the Regulator (representing the Oversight Committee), who are fighting over the Enamour. Additionally, the source includes promotional copy for several other Doctor Who books and media featuring the Eleventh Doctor, Amy Pond, and Rory Williams, such as Apollo 23, Night of the Humans, and Nuclear Time, confirming the material’s connection to the popular television series.