On Christmas Day 5343 on the human colony of Mendorax Dellora, the Doctor is mistaken by a servant, Nardole, for a surgeon hired by River Song to attend to her dying husband, King Hydroflax. River, who has not yet met the Doctor’s present incarnation, fails to recognise him and increasingly frustrates him with her flirtations with Hydroflax. River takes the Doctor aside to discuss the operation he is supposed to be performing; the Halassi Androvar, the most valuable diamond in the universe, has become lodged in Hydroflax’s brain during a raid on the Halassi vaults and is slowly killing him. River wants “the surgeon” to remove his entire head, considering it quicker and easier.
