A message transmitted down through history draws the Doctor and Amy to England in AD 102. There they find River Song waiting for them, with a warning that a legendary prison called the Pandorica, hidden beneath Stonehenge, is about to open. But the Pandorica is actually a trap set for the Doctor by a legion of his oldest enemies. And meanwhile, a mysterious force has seized control of the TARDIS, setting in motion an explosion which threatens to destroy the entire universe. With the Doctor imprisoned in the Pandorica for eternity, will silence fall across all time and space?

Ever since the return of Doctor Who in 2005, each season had featured an ongoing plot which culminated in the final story. The preference of former showrunner Russell T Davies had been to seed ideas into earlier episodes which would foreshadow the climactic adventure, as with the phrase “Bad Wolf” during Season Twenty-Seven, the establishment of the Torchwood Institute in Season Twenty-Eight, the introduction of Harold Saxon throughout Season Twenty-Nine, and finally the lost planets and missing bees of Season Thirty.

For Season Thirty-One, new executive producer Steven Moffat wanted to continue this tradition, and planted appearances by the sinister crack in time throughout the year's stories. Conversely, Moffat also sought to incorporate elements from each of the preceding adventures into his two-part season finale, which meant that he had to start planning the serial at a very early stage. As such, Moffat was able to realise one concept he was keen to attempt, by including a scene in the season's fifth episode, Flesh And Stone, which (unbeknownst to viewers at the time) would actually feature the time-displaced Doctor of the finale.

The plan also required Moffat to script some material for the climactic adventure which could be filmed alongside various episodes throughout the production schedule, to take advantage of the availabilities of castmembers and locations. As a result, several scenes intended to form part of the pre-credits sequence for the season's penultimate episode were directed by Andrew Gunn during Block Two of recording. On August 26th, 2009, a scene featuring Prime Minister Winston Churchill and Edwin Bracewell from Victory Of The Daleks, set in Churchill's offices, was taped at the bunker of the Joint Resilience Unit in Swansea. This was followed on August 31st by a shot of Bracewell hurrying along a corridor, which actually took place at Brackla Bunkers in Bridgend. Then, on September 22nd, Gunn shot elements of a scene involving Liz Ten (from The Beast Below) and River Song in Buckingham Palace, at the Orangery in Margam Country Park, Margam. On December 3rd, during work on Block Five, an establishing shot of Vincent Van Gogh's Yellow House (as seen in Vincent And The Doctor) was captured by director Jonny Campbell in Vrsine, Croatia on December 3rd.

While all of this preliminary work was going on, Moffat and his fellow executive producers, Piers Wenger and Beth Willis, learned that their original plan for the season's shooting schedule was not feasible. The intention had been to make the two-part finale as Block Seven, the last recording block of the year. However, early in the autumn, it became clear that this would give effects house The Mill insufficient time to complete what would no doubt be an ambitious pair of episodes; instead, the finale would have to be made as Block Six. Effectively stripped of nearly two months' writing time, Moffat spent the remainder of 2009 busily completing his scripts, which became known as The Pandorica Opens and The Big Bang. His drafts of the two episodes were completed on December 1st.

Part of Moffat's intention with the finale was to engage in a spot of wish-fulfillment by confronting the Doctor with an army of his past foes. (The Pandorica Opens would ultimately feature either appearances by, or references to, the Daleks, the Cybermen, the Sontarans, the Autons and the Nestene Consciousness, the Silurians, the Judoon, the Sycorax, the Hoix, the Roboforms, the Weevils, the Blowfish aliens, the Uvodni, the Zygons, the Draconians, the Slitheen, the Drahvins, the Atraxi, the Terileptils, and the Chelonians. The latter had never been seen on television in Doctor Who or its spin-offs, but had made several appearances in the Doctor Who: The New Adventures range of novels published by Virgin Books in the 1990s, starting with 1993's The Highest Science by Gareth Roberts.) Moffat felt that such an epic showdown demanded an equally epic setting, and this led him to situate the key events of The Pandorica Opens around (and below) Stonehenge.

In addition to referencing the season's various stories, Moffat also wanted the finale to play with the possibilities of time travel more directly than Doctor Who had attempted in the past. To this end, he incorporated a complex sequence in which the Doctor hopped back and forth through time in order to save Amy and then gain access to the Pandorica. Moffat acknowledged that this kind of paradoxical business could undermine the drama of Doctor Who, but felt that the universe-ending threat of the story warranted such rule-breaking by the Doctor. He also sought to make use of the notion of a character travelling backwards along his own timeline. This was a concept he remembered encountering in The Making Of Doctor Who, the milestone behind-the-scenes chronicle of the series written in 1972 by Malcolm Hulke and Terrance Dicks.

With Gunn and Campbell having made their contributions to The Pandorica Opens / The Big Bang, the reins of the serial were now turned over to director Toby Haynes. Haynes was a lifelong Doctor Who fan whose previous credits included MI High, Spooks: Code 9, Being Human and Five Days. His first day of recording came on December 15th at Sutton Farm in Llandow, while Block Five was still in production. On this date, Haynes took the director's chair from Campbell after a day of work on Vincent And The Doctor to record the pre-credits scene involving Van Gogh.

Block Six proper got under way on January 14th, 2010 at Upper Boat Studios, the first of two consecutive days devoted to scenes in the TARDIS. Next, the National Museum housing the Pandorica was actually Brangwyn Hall in Swansea. Work there spanned January 18th to 23rd, and also included shots of the Doctor piloting the Pandorica. Caitlin Blackwood returned to play the young Amelia, as she had in The Eleventh Hour; this time, however, she actually got to share screentime with her cousin, Karen Gillan. Additional material in the National Museum -- particularly in the foyer -- was then taped, appropriately enough, at the National Museum of Wales in Cardiff on the 25th. The same day, more Cardiff recording included the Stormcage sequence at Millennium Stadium, and River's meeting with Dorium in the Maldovarium, which occurred at the Crystal nightclub.

On January 26th, the Miskin Manor Hotel in Llantrisant provided the venue for Amy and Rory's wedding reception. Work there concluded on the 27th, at which point cast and crew relocated to the Vicarage in Rhymney, which was again serving as Amy's house in Leadworth. Haynes' team remained at the Vicarage until the 29th; on the last day, the scene in Rory's bathroom was also filmed there. On February 1st, the grounds of Margam Country Park were the site of the Roman encampment, and also afforded Haynes the opportunity to record the Doctor, Amy and River traversing the English countryside.

The centrepoint of the shoot came on February 2nd, the lone day that Haynes and his team would spend at Stonehenge, near Salisbury in Wiltshire. Because the stone circle was open to the public for much of the day, cast and crew had to take full advantage of the time in-between, and especially of the limited hour of daylight they enjoyed on the morning of the 3rd. That night, the Doctor Who team returned to Margam Country Park for additional Stonehenge footage, this time at a replica that had been constructed which the crew dubbed “Foamhenge”. Work there continued through to the 5th and allowed for shots forbidden at the real Stonehenge, such as the Doctor standing atop one of the megaliths. Also on the last day, the Orangery at Margam once again represented Liz Ten's Buckingham Palace, this time for River Song's half of her encounter with the future monarch.

The rest of principal photography was largely scheduled to take place at Upper Boat. On February 6th, scenes in the Centurions' tent were taped alongside further material in the TARDIS. Work on the 8th began with sequences inside the Pandorica, before proceeding to the massive “Underhenge” set -- this was the largest set yet created for Doctor Who, and was designed to evoke the feel of Steven Spielberg's 1981 blockbuster Raiders Of The Lost Ark. On the 9th, the cast was joined by actor Tim Baggaley who, as an amputee, was able to bring the one-armed Cyberman to life without the need for complicated effects work. On the 10th, both the Pandorica chamber and TARDIS sets were in use, and Haynes continued to record scenes in the Underhenge on the 11th, 12th, 15th and 16th.

The last day of Block Six was February 17th, which again saw filming take place on the sets for both the TARDIS and the Underhenge, along with several pick-up and effects shots -- such as the Doctor and Amy seeing River's message on Planet One. At the same time, a long shot of the Doctor, Amy and River on horseback was recorded using stand-ins at Gelligaer Common in Gelligaer. Haynes taped additional inserts -- largely involving the headless Cyberman -- at Upper Boat on March 3rd. This left only the scene of the Doctor watching as Amy leaves the note which will direct him to Craig Owen, as implied by the events of The Lodger. This was filmed in two parts, at Westville Road in Cardiff on March 4th and at Taff Terrace in Radyr on March 18th.

In keeping with the narrative, The Big Bang aired on the date of Amy and Rory's wedding -- June 26th -- and brought Doctor Who's thirty-first season to a close. Despite the complete changeover of cast and production team, the programme continued to be a massive success, regularly placing within the Top Twenty shows of the week in the UK. Even more remarkably, Doctor Who was tapping into new audiences, as it had become one of the most popular downloads via the BBC's iPlayer platform, and was also reaching unprecedented heights of popularity in North America. 2010 was a year of transition for Doctor Who, but its latest regeneration had simply secured its future for the years to come...

• Doctor Who News.
• Doctor Who Magazine Special Edition #27, 16th March 2011, “The Pandorica Opens / The Big Bang” by Andrew Pixley, Panini Publishing Ltd.