The sun of the gemstone-rich planet Midnight is hostile to all life, but a leisure complex has been constructed there which filters out its deadly radiation. While Donna enjoys some rest and relaxation, the Doctor takes a transport to the famed Sapphire Waterfall. An obstruction on the planned route prompts the transport to take a previously-unexplored path. Suddenly, the vehicle comes to a stop -- and, impossibly, something begins banging on the exterior. As a strange intelligence possesses one of the passengers, the Doctor finds himself fighting a losing battle against the rising tides of panic and paranoia.

Doctor Who's thirtieth season was to mark the third year in a row that two production blocks would be operating simultaneously. This practice of double-banking had begun with Season Twenty-Eight, when the addition of a Christmas special to the recording schedule meant that fourteen episodes now had to be made during a period originally intended for only thirteen. On the two previous occasions, the double-banking was achieved by concentrating an episode around a newly-introduced character: Elton Pope in 2006's Love & Monsters and Sally Sparrow in 2007's Blink. For Season Thirty, however, executive producer Russell T Davies decided to try a different approach. His idea was to split up his regular cast, so that the double-banked episodes would include one story focussed on the Doctor, and another showcasing Donna Noble. The latter would be Turn Left, made as the year's seventh recording block, while the Doctor-centric adventure was intended to be Tom MacRae's “Century House”, which would be paired with The Doctor's Daughter as Block Six under director Alice Troughton.

However, as pre-production loomed in September 2007, Davies was becoming less enamoured of “Century House”. It was planned to be the season's eighth episode, following The Unicorn And The Wasp, and Davies was concerned about having consecutive stories with a distinctly comedic bent. Furthermore, the slot occupied by “Century House” would be the fiftieth full-length episode to be broadcast since Doctor Who returned in 2005, and Davies felt that this milestone deserved a truly novel storyline.

Russell T Davies wanted to explore what would happen to people under siege who gave in to their fears and baser natures

Finally, towards the end of the month, Davies began to consider the possibility of writing a replacement script for “Century House” himself. He quickly devised the notion of an isolated band of accident survivors, stranded in a transport on an alien planet, being infiltrated by a creature which could steal their very words. Davies was inspired by the aggravating childhood habit of mimicking another's words, and by the idea of an alien race which seemingly spoke gibberish, as suggested by the 1991 Star Trek: The Next Generation episode Darmok. The setting was influenced by the 2003 horror film Jeepers Creepers II, about a high school basketball team which was trapped on a bus by an ancient monster. Davies also drew upon his experience of writing the 2007 Christmas special, Voyage Of The Damned, in which a small group of people under siege behaved with the utmost courage and nobility. Now he wanted to explore what would happen in a similar situation if those involved instead gave in to their fears and baser natures.

Davies wrote his script swiftly; the first draft was completed on October 18th, just a few days after “Century House” was officially dropped from the schedule. The adventure came to be called Midnight, although Davies alternatively considered “Crossing Midnight”. There were few major changes to the narrative as it developed, although timing considerations forced the elimination of a sequence in which the possessed Sky ceased mimicking the other passengers, one by one, until she focussed solely upon the Doctor. The transport that formed the principal setting of Midnight was originally referred to as Crusader 5, until Doctor Who Magazine columnist Benjamin Cook reminded Davies of the episode's milestone status. As such, the transport became the Crusader 50. Unusually, Midnight would be the first story since 1975's Genesis Of The Daleks in which the TARDIS made no on-screen appearance.

Amongst Troughton's cast was veteran actor Sam Kelly as Professor Hobbes. In mid-November, however, he suffered a broken leg as a result of a traffic accident. At very short notice, Kelly was replaced with another Troughton: David Troughton, the son of Patrick Troughton, who had played the Second Doctor. This would be his fourth appearance in televised Doctor Who, and his first since portraying King Peladon in The Curse Of Peladon, back in 1972. Just days earlier, Troughton had recorded Cuddlesome, a Fifth Doctor audio play for Big Finish Productions.

Unusually for Doctor Who in the twenty-first century, virtually all of Midnight was recorded in the studio, with work taking place at the regular Doctor Who facilities in Upper Boat starting on November 27th. Even more unusually, the director chose to hew largely to the story order -- a practice which had not been common on Doctor Who since the early Seventies. The first week of filming ran until November 30th; the principal set on each day was the passenger section of Crusader 50, although part of the 28th was spent taping the material in the drivers' cabin.

The following week, recording spanned December 3rd to 7th. Billie Piper briefly joined the team on the 5th to record the shot of Rose which would be glimpsed on Crusader 50's monitor screens. Some of this footage was later repurposed for a scene in the season's fifth episode, The Poison Sky. The team stood down for the weekend before returning to Upper Boat one more time on December 10th. In addition to the final scenes aboard Crusader 50, the initial sequence of the Doctor boarding the transport was also recorded. Finally, December 11th was the lone location day for Midnight, with Dylan's Health Spa at the Celtic Manor Resort in Newport providing the foyer of the leisure palace.

Meanwhile, changes were being made to the 2008 schedule. As the eighth episode of Season Thirty, Midnight would have aired between Gareth Roberts' The Unicorn And The Wasp and Steven Moffat's Silence In The Library / Forest Of The Dead. However, Davies had now realised that Donna would become trapped in an alternate reality in both Moffat's narrative and episode eleven, Turn Left. On December 10th, it was decided that Midnight should be repositioned between them, making it the tenth episode of the season. An unavoidable consequence was that the Crusader 50 reference was now deprived of its intended meaning.

Midnight was broadcast on June 14th, 2008. With a scheduled start time of 7.10pm, it saw Doctor Who continuing to drift later into the evening. I'd Do Anything had ended its run the week before, and so Midnight was instead preceded by a special edition of the quiz show Weakest Link. Remarkably, Doctor Who placed fifth in the weekly audience charts on the strength of 8.1 million viewers. Not only was this already the show's sixth Top Ten performance during 2008, but it also tied as the highest-charting regular-season episode with The Ark In Space Episode Two, which had reached Number Five in February 1975. Indeed, only Voyage Of The Damned had ever placed higher, coming in second the previous Christmas. As Doctor Who surged towards its season finale, it would become clear that this was only the beginning of a trend...

• Doctor Who Magazine Special Edition #20, 19th November 2008, “Episode 10: Midnight” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #59, 2017, “Story 196: Midnight”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Writer's Tale by Russell T Davies and Benjamin Cook (2008), BBC Books.