In August 1951, Eddie and Barbara Smith inexplicably left their infant daughter, Sarah Jane, by the side of the road. Moments later, they perished in a traffic accident. In the present day, Sarah Jane discovers a time fissure which leads back to her home town of Foxgrove in the summer of 1951. Although she suspects a trap, she and Luke travel back in time, where Sarah Jane finds herself unable to resist altering the course of events to save her parents' lives. In the process, she succumbs to a plot by the Trickster to corrupt history -- leaving Clyde and Rani to confront the Trickster's minion, the Graske, on a ruined Earth.

After completing work on Secrets Of The Stars, Gareth Roberts turned to his second serial for the sophomore season of The Sarah Jane Adventures. Of his contributions to the first season, Whatever Happened To Sarah Jane? and its Machiavellian antagonist, the Trickster, had been particularly well-received. Executive producer Russell T Davies asked Roberts to develop a rematch between Sarah Jane and the Trickster -- as well as his servant, the diminutive alien Graske. Davies suggested that their second encounter should involve the journalist's parents, who had already been established as having died when she was very young.

Roberts was working on his narrative in early 2008, although the original version was substantially different from the finished scripts. In his original conception, Sarah Jane identified a time fissure at the disused RAF Twyford, and she used it to travel back to 1951, during the airbase's heyday -- the place and time of her parents' death in a mysterious accident. Masquerading as Commander June Barlow to fool Group Captain Burfield, Sarah Jane became suspicious of research being conducted by Dr Kendrick. Clyde came through the time fissure to assist her, but the first episode ended by revealing that this was really the Trickster in disguise. In fact, her friends were actually being kept away from the fissure in the present day by the Graske.

Originally, Sarah Jane's parents sacrificed their lives by crashing a plane loaded with lethal bacteria

In the second installment, Sarah Jane discovered that Dr Kendrick was working with a lethal type of bacteria, but she did not realise that the scientist and her parents were already infected. As history was meant to transpire, they were to sacrifice their lives by crashing a plane loaded with all the remaining samples of the bacteria. Due to Sarah Jane's interference, however, these events no longer occurred, and the infection began to spread uncontrollably. Fortunately, in the present day, her friends were approached by an old woman named Jinty who had helped care for the infant Sarah Jane as a twelve-year-old on the base. Armed with Jinty's information, Luke was able to travel through the time fissure and help his mother put history back on track.

Over the ensuing weeks, the action of Roberts' story was greatly simplified, with the military element removed and the setting changed from the airbase to the rural village of Foxgrove. Luke accompanied Sarah Jane back to 1951 immediately, rather than passing through the time fissure only at the adventure's climax. Sarah Jane's parents, originally called Edward and Gloria Smith, now became Eddie and Barbara Smith -- the latter an homage to Davies' own mother. Roberts' scripts later became known as The Temptation Of Sarah Jane Smith.

Roberts' serial would be made alongside the season finale, Enemy Of The Bane, as part of the year's third and final production block. Assigned to direct was Graeme Harper, who had previously handled Whatever Happened To Sarah Jane?. Since then, Harper had worked on five episodes for the 2008 season of Doctor Who, most recently its finale, The Stolen Earth / Journey's End, in which Sarah Jane, Luke and Mr Smith had all appeared.

Around the time that The Temptation Of Sarah Jane Smith entered production, Tommy Knight was participating in workplace experience with the BBC's Art Department. Filming for the serial began on June 26th and 27th, at the show's usual studio facilities in Upper Boat. The first day covered material in the Chandra residence, while the second day dealt with scenes in the Graske's ship, as well as effects shots of the Trickster. Due to the late-summer setting of Roberts' story, Harper then elected to concentrate on Enemy Of The Bane for several days, before the scenes at Broughton New Town were recorded at Llanedeyrn Maelfa Shopping Centre in Cardiff on July 16th and 17th.

Sequences in the alternative timeline where the Trickster was victorious -- dubbed “Futureworld” in the scripts -- were filmed at Trefil Quarry near Tredegar on July 21st and 22nd. Cast and crew were meant to return to the quarry for a third day, but swift progress made this unnecessary; as such, the 23rd was instead dedicated to work on the attic set at Upper Boat. Next on the itinerary was the story's principal location: the small town of Llantwit Major, which was dressed as 1951 Foxgrove. Harper's team filmed there on July 24th and 25th, and again after the weekend from July 28th to 30th. On the last day, some time was also spent at Clinton Road in Penarth for material on Bannerman Road.

The schedule on July 31st started with sequences in the Abbey, which was actually the ruins of Old Beaupre Castle in St Hilary. Harper had then planned to return to Llantwit Major to record Sarah Jane and Luke approaching Foxgrove -- material which had been deferred from the earlier shoot due to rainy weather. However, a suitable site was instead found nearby at Beaupre Farm, saving the team some travel. The last day of principal photography for the season was August 1st. Filming for The Temptation Of Sarah Jane Smith took place at Clinton Road, before shifting to Upper Boat for some pick-up shots.

• Doctor Who Magazine Special Edition #23, 24th December 2009, “Episodes 2.9/2.10: The Temptation Of Sarah Jane Smith” by Andrew Pixley, Panini Publishing Ltd.