 Steven Moffat, head writer of the new series, said before broadcast that this would be one of the darkest openers to a series ever done for Doctor Who. Director Toby Haynes believed that the darker episodes like "The Impossible Astronaut" and "Day of the Moon" would allow the series to get into "more dangerous territory." The creation of the Silence was partly inspired by the figure from the Edvard Munch painting The Scream. Introducing the alien villains became a "big challenge" for the producers; it would tie in with the loose "silence will fall" arc that carried through the fifth series. Moffat did not wish to end the arc in the previous series, as he felt it would be "more fun" to continue it. Elsewhere in the episode, Delaware was written to be deceptively antagonistic towards the protagonists, which was based on actor Mark Sheppard's past as villains for his work in American television. Moffat was also keen on the idea of having the Doctor imprisoned with a beard in Area 51. Smith wore a glued-on beard, which was difficult to peel off.
