The TARDIS pursues an object hurtling through the time vortex to 1941 London, in the middle of the Blitz. The city is being haunted by an eerie child, his face covered by a gas mask, searching for his mother. The Doctor meets a group of orphans led by Nancy, who informs him that the mysterious child is her dead brother, Jamie. Now his horrific transformation is spreading through the city like a plague, passed from victim to victim by touch. Meanwhile, Rose is saved from certain death during an air raid by the enigmatic Captain Jack Harkness, a man from another time and place who may be the key to the mystery.

Not long after the September 2003 announcement that Russell T Davies would be reviving Doctor Who, he received a congratulatory message from Steven Moffat. The two men knew each other not only from their mutual involvement with an abortive soap opera called RU, which had been in development during 1994, but also because they were both longtime Doctor Who fans. At this stage, no decision had made on the length of Doctor Who's twenty-seventh season, but Davies indicated that he planned to commission Moffat if it turned out that there would be too many episodes for him to write on his own.

By the end of 2003, Season Twenty-Seven was fixed at thirteen episodes, which Davies' pitch document of December 8th broke up into seven standalone adventures and three two-part stories. Of the longer narratives, he planned to write the first and third himself, while the second was earmarked for Moffat. The pitch document labelled the episodes as “World War II” and “Captain Jax”. Davies liked the idea of placing the new companion, Rose Tyler, in a romantic era that was just far enough away from her own time to be disconcerting. He also wanted to introduce an additional companion who would join the Doctor and Rose for the remainder of the season. Captain Jax was envisaged as an alien soldier who had tracked an escaped child-creature to London during the Blitz. Masquerading as an English officer, he would befriend the Doctor but intimidate Rose. The introduction of Jax anticipated the season finale, where Davies planned to make use of his military prowess.

Jack's relationship with Rose was made more flirtations, helping to establish the character as pansexual

Moffat was formally approached about writing the serial on December 10th. Soon thereafter, it was decided to change Captain Jax's name, given the recent introduction of soundalike companions Trix in the Eighth Doctor novels from BBC Books and Hex in Big Finish Productions' Seventh Doctor audio plays. He would now be Captain Jack Harkness, reusing a surname Davies had previously employed in Century Falls and The Grand, in reference to the ancient witch Agatha Harkness of Marvel Comics' Fantastic Four and Avengers titles. Moffat suggested making Jack a human from the future rather than an alien, to avoid having too many extraterrestrials present in 1941 London. His relationship with Rose was made more flirtatious, helping to establish Davies' vision of the character as pansexual.

Where Davies focussed on the romance of the period, Moffat wanted to emphasise the haunting nature of Blitz-torn London. Spending some time immersing himself in the history of the era, he was struck by the image of gas masks tailored specifically for use by children. This suggested that the child-creature of the pitch document could instead be an eerie young boy clad in a gas mask. Moffat duly renamed the episodes “The Empty Boy” and “The Empty Children”.

The initial draft of the serial gave the infected humans more elaborate powers, including the ability to levitate and generate waves of force. Constantine was originally called Summers, and it was he who brought the Doctor to the hospital after meeting at the club. The material at the hospital was more horrific, depicting a skeleton and organs in jars, all sporting gas masks. The street urchins were protected by a woman named Miss Timberlake and a man called Mr McTavish. It was ultimately revealed that Timberlake was Nancy's mother and McTavish was really the German father of Nancy's child. The urchins were all present at the climax, having succumbed to the infection. The crashed vessel at the heart of the mystery was Jack's ship, having been catapulted back in time following the explosion of its warp drive.

Around June 2004, John Barrowman was approached about playing Captain Jack on the recommendation of executive producer Julie Gardner. The star of several stage musicals, he was a native of Scotland but had moved to the United States during his youth. As such, he was able to give a camera test in which he read Jack's dialogue in both his original Scots accent and the American accent he had cultivated during his teenaged years, plus a practised English accent. It was finally decided to opt for the American accent with which he normally spoke. Barrowman's casting was formally announced by the BBC on August 4th.

By September, the two episodes were retitled The Empty Child and The Doctor Dances. Moffat had simplified various elements, particularly by introducing the Chula ambulance as the source of the infection. It was named for an Indian restaurant where Moffat and fellow writers Mark Gatiss, Robert Shearman and Paul Cornell had had dinner on March 2nd to celebrate their Doctor Who contracts. Miss Timberlake was now dropped while McTavish had become John, an apparently mute man who hovered around Nancy.

Concern arose that the Doctor did not meet Nancy until the very end of the narrative, so her role was expanded

Summers was renamed Constantine, and was no longer present at the club. Instead, the Doctor was led to the hospital -- now identified as Albion Hospital, the setting for some of episode four, Aliens Of London -- by one of the children, who was called Billy. However, concern then arose that the Doctor did not meet Nancy until the very end of the narrative, so she was given Billy's role. The nanogenes were originally called nanites; the new terminology was suggested by script editor Helen Raynor after it was observed that nanites were a plot device often used in the various Star Trek television series.

The Empty Child and The Doctor Dances were the ninth and tenth episodes of Season Twenty-Seven, and were intended to form the year's fourth production block. Episode seven, The Long Game, was extracted from Block Three at a late stage due to its effects requirements, to be made on its own in what was dubbed “Block 4A”. As such, The Empty Child / The Doctor Dances was now considered to be “Block 4B”. The director would be James Hawes, who had previously been a candidate for Block One.

Only two days of production occurred during 2004, with special effects shots completed on December 17th and 18th at Doctor Who's usual studio home of Unit Q2 in Newport. The first day marked Barrowman's debut as Captain Jack. By now, the design department had spotted the recurrence of the phrase “bad wolf” in the season's scripts, as part of the overarching storyline which Davies had been developing. They wrote its German equivalent, “schlechter wolf”, on the side of the Nazi bomb, which spared Davies and Moffat the need to introduce the phrase elsewhere in the serial.

Following the holidays, work resumed in 2005 with four days at the Cardiff Royal Infirmary, from January 4th to 7th. It posed as Albion Hospital, as it had during the making of Aliens Of London. Scenes in the alley where the TARDIS materialised were filmed off Womanby Street in Cardiff on the 9th and 10th; the latter day also saw Headlands School in Penarth dressed as the club. More work at the Infirmary followed, from January 11th to 14th. In order to achieve the necessary height, shots of Rose dangling from the barrage balloon were filmed alongside some footage of the bomb, in a hangar at RAF St Athan on January 17th. Hawes' team then returned to Unit Q2 from the 18th to the 20th. The main focus was material aboard Jack's ship, although some sequences in the TARDIS were completed on the last day.

The next major venue was the Chula vessel's crash site, on the Barry premises of the Vale of Glamorgan Railway. Coincidentally, it lay directly across the road from the holiday camp -- now mostly demolished -- where Delta And The Bannermen had been taped in 1987. Recording there began on January 21st and continued from the 23rd to the 27th, with some inserts also captured on the 23rd. Lighting the location proved to be a challenge. Director of photography Ernie Vincze erected a single large arc lamp, which proved to be visible from a great distance, becoming an irritant and a traffic hazard. A number of smaller lamps were used instead, slowing the pace of production to the point that some material had to be dropped or rewritten for the studio.

On January 28th, a house on Bargoed Street in Cardiff posed as the exterior of the Lloyd residence. Sequences set in its interior were recorded at Unit Q2 on the 31st. Around the same time, Moffat wrote new material for The Doctor Dances while on holiday in Australia, compensating for the loss of some of the planned Barry footage. Because the latter stages of work on his serial would be running in parallel with episode eleven, Boom Town, Moffat was asked to use only Nancy and the street urchins. He suggested a scene in which the Empty Child took control of a record player, although it was ultimately replaced by a typewriter.

The next work on The Empty Child / The Doctor Dances took place on February 7th at Unit Q2, with Hawes taping more action in the Lloyds' dining room and the TARDIS, alongside various inserts. The next day, Glamorgan House in Cardiff was used for the officers' club. The 8th and 9th were also the dates on which the barrage balloon sequences were filmed as model shots, at the BBC Model Unit Stage in Acton, London. The remaining material in the Lloyds' house was then recorded at Unit Q2 on February 9th, 11th and 25th, accompanied on the first day by further inserts.

The Empty Child would be dubbed by Noah Johnson, the son of a friend of dialogue editor Paul McFadden

Jamie, the Empty Child, was played by Albert Valentine, although Luke Perry (who had been cast as Timothy Lloyd) stood in for him in some long shots. It was originally planned that Valentine would also provide the Empty Child's dialogue but, in post-production, concerns were raised that his delivery lacked a sense of menace. The production team instead turned to Zoe Thorne, who had been the voice of the Gelth in episode three, The Unquiet Dead. However, her timbre was too obviously feminine. Finally, it was decided that the Empty Child would be dubbed by Noah Johnson, who was the son of a friend of dialogue editor Paul McFadden.

The Empty Child was the only episode of Season Twenty-Seven to be scheduled at a time other than 7.00pm. With the Eurovision Song Contest airing later in the evening on May 21st, Doctor Who was shifted back to 6.30pm, immediately after the Junior Mastermind Final. The National Lottery: Come And Have A Go still followed Doctor Who, and Strictly Dance Fever returned as its lead-in the following week.

• Doctor Who Magazine Special Edition #11, 31st August 2005, “Fact File: The Empty Child/The Doctor Dances” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #50, 2018, “Story 164: The Empty Child / The Doctor Dances”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Inside Story by Gary Russell (2006), BBC Books.