then appears and tells the Brethren to take the others into the temple for the final sacrifice. The Moon goes into eclipse, and the Brethren place their hands on the altar as a ball of Helix energy descends. However, it consumes the Brethren, expanding and then fading away. "Hieronymous" removes his mask – it was the Doctor, imitating the cult leader's voice. The Doctor explains it as a case of "energy squared", putting the Mandragora Helix back where it came from. The Doctor and Sarah make their goodbyes to Giuliano. Just before they leave the Doctor tells Sarah that while Giuliano will not have any more trouble with Mandragora, humanity will. The constellation will be in position at about the end of the 20th century. Production Working titles for this story included The Catacombs of Death and The Curse of Mandragora. The ultimate name references the masque, entertainment performed by masked players, that later plays a key role in the plot. Location shooting for the serial was done at the resort of Portmeirion in Wales, better known as the setting for the cult series The Prisoner. Cast notes Tim Pigott-Smith previously played Captain Harker in The Claws of Axos (1971). Norman Jones previously played Khrisong in The Abominable Snowmen (1967) and Major Baker in Doctor Who and the Silurians (1970). Robert James had previously played Lesterson in The Power of the Daleks (1966). Themes and analysis Martin Wiggins, senior lecturer and fellow at the Shakespeare Institute at Stratford-upon-Avon, has compared this story's plot with Hamlet: "It has an inexperienced, intellectual prince, a usurping duke, and a debate about the conflict between science and religion that recalls Hamlet's musings on the nature of the supernatural world." Broadcast and reception Paul Cornell, Martin Day, and Keith Topping wrote of the serial in The Discontinuity Guide (1995), "One of the few metaphors in Doctor Who history (nasty alien energy mass = superstition and scientific ignorance) is blurred by the lack of actual scientific understanding that the story exhibits. Looks and sounds great, though." In The Television Companion (1998), David J. Howe and Stephen James Walker reported that viewers had a mixed reaction to the serial, according to the BBC's Audience Research Report, but there had been a majority of "moderate approval". Howe and Walker themselves commended the "very well written and highly intelligent" scripts, the "polished production", and strong cast. In 2010, Patrick