Months ago, a newly-pregnant Amy was kidnapped by the Headless Monks and their agent, the ruthless Madame Kovarian. Now, on an asteroid called Demons Run, she has given birth to her daughter, Melody, who will be taken away to be used as a weapon against the Doctor. But the Doctor and Rory have called in favours and gathered a strike force to rescue Amy and Melody. Only River Song refuses to heed the Doctor's summons. She knows that this is the day of the Doctor's greatest victory, and his greatest defeat... and the day that he will finally learn who she really is.

For his first season in charge of Doctor Who, executive producer Steven Moffat had largely hewed to the format established by his predecessor, Russell T Davies. However, when it came to planning Season Thirty-Two, Moffat decided to introduce some innovations. One concern he had developed was that Doctor Who's lengthy thirteen-part season was both a blessing and a curse, since it presented a challenge in holding the attention of casual viewers. In particular, with the season premiere scheduled around Easter, the latter episodes inevitably aired as summer was hitting its stride and viewing numbers dwindled across the television landscape. It was now becoming increasingly common in the industry for a season to be divided into two halves; this approach had the added benefit of allowing for a “mid-season finale” which could attract considerable publicity. Moffat intended to experiment with this format for Season Thirty-Two: the first seven episodes would be transmitted in Spring 2011 and end on a massive cliffhanger, with the remaining six installments following in the autumn.

This meant that Moffat would need to develop both an overall story arc which would link all thirteen episodes, and also a shorter storyline which would be resolved in the mid-season finale. He decided that the first half of the season would build up to the revelation of River Song's true identity as the daughter of Amy and Rory. This was part of Moffat's overarching plans for Doctor Who, and indeed he had given Amy the surname Pond as a link to the other woman's forename. Furthermore, the Season Thirty-One finale had been titled The Big Bang in part as a naughty allusion to Amy and Rory's activities as the TARDIS took them away for their honeymoon -- namely, that River was being conceived as the closing credits rolled.

Steven Moffat was sensitive to the difficulties it would pose if Amy were to be adventuring while with child

More broadly, Moffat felt that it was important for Amy and Rory to become parents in order to further distinguish the notion of a married couple aboard the TARDIS from the more casual relationships which had previously been observed between companions. At the same time, he was sensitive to the dramatic difficulties it would pose if Amy were to be adventuring with the Doctor during the nine months she was with child. He considered simply skipping to the end of the pregnancy, but soon developed the notion of Amy being replaced by a doppelganger. The mid-season finale would then focus on the Doctor and Rory's quest to rescue Amy and her newborn baby. Moffat completed a first draft of his script on December 17th, 2010. At this point, it had no title; Moffat was leaning towards either A Good Man Goes To War or “His Darkest Hour”, but the cast soon took to calling it “Demons Run”.

A centrepiece of Moffat's story involved various allies of the Doctor coming to his aid. Some would be new characters, most notably the Silurian Madame Vastra, her partner Jenny Flint, and a Sontaran named Strax who was inspired by Gareth Roberts' unused Season Thirty-One script, “Death To The Doctor”. Others would return from the Eleventh Doctor's earlier adventures, including the Spitfire pilots from Victory Of The Daleks and the black marketeer Dorium Maldovar from The Pandorica Opens. Added at a late stage were Captain Henry Avery and his son, Toby, from The Curse Of The Black Spot, which would follow Moffat's script into production; originally, it was Rory who prevented Kovarian's departure. Moffat also reached further back into Doctor Who's history, adding the Judoon (first encountered in 2007's Smith And Jones) and Ood Sigma (introduced in 2008's Planet Of The Ood). For a time, he hoped to include the Doctor's former companion, Captain Jack Harkness, whom he had created for 2005's The Empty Child / The Doctor Dances. However, it was soon learned that actor John Barrowman would be reprising the role for the fourth season of the spin-off series Torchwood, and its production in America would likely clash with the relevant recording dates.

One of the ideas which Moffat incorporated into his script had been at the back of his mind for at least fifteen years, when he wrote about it in a post for the Usenet newsgroup rec.arts.drwho on January 8th, 1995. This was the notion that the word “doctor” was derived from the Doctor's own assumed name, rather than the other way round. Concerned about the episode's surprise leaking out, Moffat devised several false endings to the script, one of which -- a putative revelation about the Doctor's true name -- was even used for the readthrough on January 6th, 2011. Matt Smith and Alex Kingston had already been alerted to the adventure's real climax, however, and Moffat privately explained the truth to a suspicious Karen Gillan and Arthur Darvill immediately after the readthrough ended.

Neve McIntosh would appear as Vastra, after playing the Silurians Alaya and Restac in Season 31

The director assigned to the story was Peter Hoar, whose interest in the medium of television had been stoked by Doctor Who during his childhood. It would be made alone as the fourth recording block for the season, officially labelled “Block Four-A” (with The Curse Of The Black Spot, directed by Jeremy Webb, forming “Block Four-B”). A pair of familiar faces joined the cast in new roles. Neve McIntosh would appear as Vastra, after playing the Silurians Alaya and Restac in Season Thirty-One's The Hungry Earth / Cold Blood; Moffat's script specified that Vastra was from the same “gene code” as Alaya. Meanwhile, Strax would be the third Sontaran for Dan Starkey, dating back to Season Thirty's The Sontaran Stratagem / The Poison Sky.

New to Doctor Who was Welsh actress Catrin Stewart, who had appeared with McIntosh in a 2010 production of the play The Lady From The Sea and would now portray Jenny. The two actresses privately fleshed out their characters' mutual history, and agreed that Jenny was an orphan who had been adopted by Vastra as a child, and now shared her bed. Cast as Madame Kovarian was veteran actress Frances Barber. Although the character would be seen in earlier episodes of the season -- where she would be credited as “Eye Patch Lady” -- the mid-season finale would actually mark her first filming for the role.

The first day of production was January 11th, when Aberthaw Cement Works in East Aberthaw provided the battlefield where Strax was introduced. Later that day, Penllyn Castle in Penllyn offered the drawing room and corridor in Madame Vastra's house. On the 12th, scenes in the Headless Monks' conversion chamber and in the underbelly of Demons Run were filmed at Uskmouth Power Station in Newport. The main location for the episode was the massive “super hangar” at MOD St Athan, which was used as the Demons Run concourse. Work there took place on January 13th and 14th, and resumed after the weekend from the 17th to the 19th.

A busy January 20th in Cardiff saw Hoar's team start the day at Laguna Health and Spa in the Park Plaza Hotel, which became the Maldovarium. Later, Stormcage material was filmed at the Millennium Stadium, and finally the Victorian street was really The Maltings. At short notice, an extra day at MOD St Athan was scheduled for January 21st. On the 22nd, cast and crew wrapped up the week at Doctor Who's regular studio home in Upper Boat, with the start of recording on the set for the security control room.

After a day off on Sunday the 23rd, January 24th to 26th were spent back at Upper Boat. Activity was chiefly concentrated on the birth room, although Hoar also completed the sequences in the security control room on the first day, while additional recording on the last day involved material in the airlock corridor and on the concourse. On January 27th, cast and crew relocated to the premises of Fillcare in Pontyclun. The focus was on Rory's confrontation with the twelfth Cyber legion, for which the Cyberman costumes had been altered to remove the Cybus Industries ‘C’ logo from the chestplate. Corridor scenes set in both the Maldovarium and on Demons Run were also recorded. At the same time, producer Marcus Wilson directed the online prequel which would accompany the episode, in which Dorium provided information to the Headless Monks. This was also the day on which Barber recorded her cameo appearances for the season's earlier adventures.

The remaining material for the mid-season finale was confined to Upper Boat. First to be recorded was the footage of Henry and Toby Avery, during production on The Curse Of The Black Spot on February 8th. A pick-up shot of the lettering on the Doctor's crib was taped on February 14th. On March 20th, Julian Simpson -- who had directed the preceding story, The Rebel Flesh / The Almost People -- was brought aboard to oversee a variety of new and alternative shots for the Battle of Demons Run. Hoar was unhappy that he was not involved with this work, and he came to feel that internal politics were to blame. More inserts were then captured on March 28th and April 6th.

Paul Kasey's appearance as Ood Sigma was edited out of A Good Man Goes To War

During post-production, Moffat finally settled on A Good Man Goes To War as the episode's title. In order to avoid sacrificing narrative coherence, it was allocated a fifty-minute timeslot. Frequent Doctor Who scriptwriter Mark Gatiss made an uncredited cameo as the voice of the Spitfire pilot, which he had also provided for Victory Of The Daleks. However, Paul Kasey's appearance as Ood Sigma was edited out of the story; he was to fight for the Doctor by singing a melody which forced the Headless Monks into prayer. Despite the cut, Russell T Davies would nonetheless receive a credit as the Ood's creator.

Running to ninety-nine seconds, the prequel to the mid-season finale was made available on May 28th, directly after the broadcast of The Almost People. One week later, on June 4th, A Good Man Goes To War brought the first half of Doctor Who's thirty-second season to a close. Given its extra length, it aired five minutes earlier than recent installments, at 6.40pm. The results show for So You Think You Can Dance was pushed later in the schedule, and so Doctor Who was followed by the National Lottery quiz show Who Dares Wins on this occasion. During the twelve weeks that followed, the Doctor Who timeslot was largely filled by family films and the third season of John Barrowman's talent show, Tonight's The Night. But viewers would have to wait until the end of August to catch up with the Doctor's search for Melody Pond...

• Doctor Who Magazine Special Edition #30, 21st March 2012, “A Good Man Goes To War” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #68, 2017, “Story 218: A Good Man Goes To War”, edited by Mark Wright, Hachette Partworks Ltd.