The Doctor, Amy and Rory are confronted by a cryptic figure who calls himself the Dream Lord. The Dream Lord has caused the three time travellers to flit back and forth between two different realities -- one in which they're stranded aboard a crippled TARDIS, the other in which Amy and Rory have settled down in Leadworth and are about to become parents. In both cases, the trio face a mortal danger... but they first have to deduce which is the true reality, or risk becoming trapped in the dream for the rest of their lives.

By 2008, Simon Nye was a veteran television scriptwriter whose credits included Is It Legal?, How Do You Want Me?, Hardware and a TV movie adaptation of The Railway Children. However, the programme which had launched his career was the raunchy sitcom Men Behaving Badly, which was based on Nye's 1989 novel of the same name. Nye had been encouraged to adapt Men Behaving Badly for television by producer Beryl Vertue, and it was through Vertue that he later came to know her son-in-law, Steven Moffat, who was also making a name for himself as one of Britain's top comedy writers. When Moffat became Doctor Who's showrunner in 2008, Nye indicated that he was interested in writing for the programme. However, Nye's busy schedule meant that it was not until 2009 that he could confirm his availability to contribute a script for Season Thirty-One.

At this stage, Moffat's conception of his first Doctor Who season was well-formed. Aware that Nye was skilled at writing interpersonal relationships, Moffat asked him to devise a story which would deal with the love triangle, of sorts, entangling the Doctor and his companions, Amy and Rory. In particular, Moffat wanted the script to firmly establish Amy's deep love for Rory -- an important development because Nye's episode would come immediately before The Hungry Earth / Cold Blood, the adventure which would climax with Rory's death. Nye's tale was also conceived with an eye on the programme's budget, requiring a small guest cast and making substantial use of the standing TARDIS set. Similarly, Nye's aliens, the Eknodines, could be straightforwardly realised, although there was some indecision as to whether one or two eyeballs should emerge from the mouths of the possessed senior citizens.

Nye's script, entitled “The Dream Lord”, was scheduled to be made as part of Block Seven -- the final production block for Season Thirty-One -- alongside The Lodger. The director was Catherine Morshead, who had directed Nye's script for The Railway Children, as well as episodes of programmes including Heartbeat, The Bill, Shameless and Ashes To Ashes. Given the nature of the episode, Morshead spent more time than usual recording on the TARDIS set at Upper Boat Studios, including the first three days of work on “The Dream Lord” from February 18th to 20th, 2010. More TARDIS filming took place there on the 22nd; by now, the console room had been given a frozen appearance using a spray of wax and plastic.

The first location for “The Dream Lord” was Skenfrith Village in Monmouthshire, which posed as Upper Leadworth from February 23rd to 25th. The filming which took place there included the sequences at the ruins -- actually Skenfrith Castle, which had been derelict since the sixteenth century. The portrayal of this site as the destination of a school field trip replaced material originally set in a primary school playground. Next, Keepers Cottage near Cowbridge served as Amy and Rory's home in Upper Leadworth. Morshead's team recorded scenes there on the 26th, and again on the 1st and 2nd of March. On the 3rd, AP Young Butchers in Llantwit Major provided the Doctor's temporary refuge from the Eknodines. Next, cast and crew spent March 6th at Lanelay Hall in Pontyclun, Llantrisant, which was dressed at the rest home.

It was back to Upper Boat on March 9th for more scenes in the TARDIS. Morshead then spent several days devoted to The Lodger, with work on “The Dream Lord” finally resuming on the 19th. More TARDIS footage was captured on this day, as were sequences on the laneways of Upper Leadworth (especially in the camper van), recorded on Eglwysilan Road in Abertridwr, Caerphilly. Filming wrapped up on March 20th, when the remaining TARDIS material -- plus effects shots and inserts -- was completed at Upper Boat.

Around this time, the decision was made to rename the story Amy's Choice. This echoed the title of the 1979 novel Sophie's Choice by William Styron (as well as its 1982 film adaptation starring Meryl Streep), about a Jewish woman at a Nazi concentration camp who is forced to choose which of her two children will be executed.

• Doctor Who News.
• Doctor Who Magazine Special Edition #27, 16th March 2011, “Amy's Choice” by Andrew Pixley, Panini Publishing Ltd.