The Doctor, Romana and K·9 visit an old friend, a retired Time Lord named Chronotis. Now living as a professor at Cambridge University, Chronotis wishes to return a book he took from Gallifrey. But the book has been inadvertently acquired by two college students, Chris Parsons and Clare Keightley, who discover that it does strange things to time. Also in pursuit of the book is the evil scientist Skagra, who uses his technology to drain the knowledge from Chronotis' mind. Before he dies, Chronotis gives Romana a mysterious warning... but what is Shada?

Although producer Graham Williams and script editor Douglas Adams had intended to showcase new writers during Doctor Who's seventeenth season, a series of scripting misadventures had derailed these plans. Already, Williams had been forced to proceed with one story -- The Horns Of Nimon -- despite significant concerns about the strength of the material and, by late June 1979, he was still searching for a season finale. Williams was contemplating leaving Doctor Who after the current run of episodes, and so he was keen that this last serial be particularly memorable. Indeed, he had allocated the year's budget in such a way as to ensure that the finale would not be made on a shoestring, as had been the case with The Invasion Of Time and The Armageddon Factor during his first two years on the job.

Finally, he was left with no other choice but to seek permission for Adams to write the six-part adventure, despite the fact that the BBC usually frowned on script editors writing for their own programme. This was formally requested on July 18th and granted on August 15th, but Adams had begun working on the storyline from around the end of June. Initially, Adams considered developing an idea he had had for a two-part serial, in which the Doctor retired -- only to find himself constantly summoned out of seclusion. Williams rejected this idea, which he felt would be perceived as self-mockery.

Douglas Adams decided to set Shada at his alma mater: Cambridge University

Instead, Adams decided to delve once more into the mythos of the Doctor's home planet, Gallifrey. This was something which Williams had actively avoided since The Invasion Of Time, because he thought that Time Lord society had become overexposed. However, it was now agreed that this would present an opportunity for a relevant story about capital punishment, by exploring what a highly-advanced civilisation would do with their worst criminals. To help ease Williams' concerns, Adams decided to set the adventure away from Gallifrey itself. He opted instead for his home town of Cambridge, and especially his alma mater: Cambridge University. This would permit Adams to draw upon his own experiences as a university student.

At the time, however, Adams was extremely busy working on various iterations of The Hitchhiker's Guide To The Galaxy. Consequently, he and Williams worked closely together on what became known as “Sunburst”, much as they had done while reworking City Of Death earlier the same year. Nonetheless, Williams decided that Adams should receive the sole credit on the scripts, in consideration of the fact that Adams' writing career would continue beyond his time on Doctor Who. One of Williams' chief concerns was to ensure that costs remained manageable, and so the cast of characters was kept very small.

The hastily-conceived “Sunburst” evolved quickly; Adams was not entirely happy with the resulting scripts, which he felt were bloated. Chronotis originally perished in Episode Two, but Adams had become fond of the character and decided to bring him back. The Krargs were initially called Kraags -- an anagram of the name of the main villain, Skagra. Adams named university students Chris Parsons and Clare Keightley after his friend Chris Keightley, president of the Cambridge Footlights. The Thinktank scientists bore names associated with Greek islands, where Adams had recently vacationed. Santori came from the island of Santorini, which was also called Thira and was formed from a volcanic caldera. Both Akrotiri and Ia were villages there. Amusingly, the Episode One joke in which Professor Chronotis forgot that he had a mind like a sieve was taken from a story that Adams had written when he was just twelve years old, and had been published in the February 27th, 1965 edition of the Eagle And Boy's World.

On August 2nd, Head of Serials Graeme MacDonald wrote to Williams to comment on “Sunburst”. He agreed with Adams' own assessment that the serial was too thin for its six-episode length, although his suggestion that the material be bolstered by a romantic subplot between Romana and Chris Parsons was ignored. By late August, the adventure had been retitled Shada. Originally, its director was intended to be Michael Hayes, who had last worked on City Of Death. In the event, however, Hayes was replaced by Pennant Roberts, whose most recent Doctor Who credit had been on the previous season's The Pirate Planet, also scripted by Adams.

All of the location filming for Shada took place in Cambridgeshire, beginning on October 15th. The main item on the first day's agenda was the Doctor and Romana punting on the River Cam near King's College. Tom Baker had considerable difficulty manoeuvering his craft, much to the consternation of Lalla Ward -- and the amusement of the spectating undergraduates. The same day, Roberts recorded some scenes on the streets of Cambridge. The 16th was spent in Grantchester for the death of the fisherman, plus sequences in the field where Skagra's invisible ship landed and on the nearby country road.

Unfortunately, the first intimations of labour unrest touched Doctor Who on this day. This was the latest in a virtually annual series of industrial disputes which had already plagued the recording of The Invasion Of Time and The Armageddon Factor in recent years. In this instance, Roberts had booked two lighting crews for the ambitious nighttime chase sequence which was intended to form the climax of Episode Two; it was due to be recorded on the 18th. Roberts' plan was to tape a scene with one team while the other went ahead to set up the next location. However, the unions recognised Doctor Who as an important target and, on the 16th, they summoned the lighting chargehand back to London. As a result, Roberts had to abandon a planned shot of the Doctor travelling to the Cavendish Laboratory in Cambridge, where Chris was meant to have his lab.

The main location for October 17th was Emmanuel College, posing as St Cedd's. Originally, Williams and Adams had hoped to film these sequences at Adams' own college, St John's, but their request had been denied in mid-July. Additional street scenes were also completed on this day. On the 18th, the continued absence of the lighting chargehand meant that the scheduled night shoot had to be cancelled. Instead, Roberts and Williams decided to rewrite the scenes for daytime recording on the 19th. With these amendments completed, Roberts retired with Baker to a local pub. There they were approached by the secretary of the St John's Choristers, who offered the use of his organisation's services. As part of filming on various Cambridge roadways the next day, the Choristers appeared during the chase sequence, singing the 1941 standard Chattanooga Choo Choo. In return, Baker was made an honorary fellow of St John's College.

During rehearsals, many of the castmembers contributed additional comedy material

With the troubled location shoot concluded, effects work took place on October 22nd at the BBC Television Film Studios in Ealing, London. Rehearsals for the first studio session then got under way, during which the scripts continued to be fine-tuned and many of the castmembers contributed additional comedy material. Recording began with a three-day block from November 3rd to 5th, and took place at BBC Television Centre Studio 3 in White City, London. Roberts' primary focus was the set for Chronotis' study, which was in use on all three days. The Thinktank scenes for Episode One were taped on the first day, while those in the dilapidated version of the space station were completed on the last day. Work on the 5th also included the sequences in the brig of Skagra's ship, together with some model shots.

More model and effects work was scheduled for Ealing on November 15th and 16th, but it appears that these dates were cancelled, possibly due to the escalating industrial action. Recording on Shada should have continued with a two-day studio block on the 19th and 20th in TC6 and, indeed, camera rehearsals went ahead as scheduled on the morning of the first day. After lunch, however, cast and crew returned to the studio to find the doors locked: the labour dispute had forced the postponement of all recording at Television Centre. Although Roberts hoped that work might resume on the 20th, the facilities remained inaccessible.

The fate of Shada was now unclear. Three further studio days were planned for December 1st to 3rd in TC3 but, as the strike dragged on, Roberts' team was faced with a new problem. Many of the productions which had been impacted by the job action were Christmas programmes, which the BBC deemed to be critical to their broadcast schedule. Consequently, it was unlikely that Shada would retain its original recording dates, even if the strike was resolved in time. Roberts proceeded with rehearsals but, after meeting with MacDonald on November 30th, Williams informed the director that the production was to stand down. As it happened, the BBC reached an agreement with the unions later the same day.

Eager for his Doctor Who swansong to be completed, Williams continued to investigate the possibility of remounting the five abandoned studio days later in December. It quickly became clear, however, that Shada could not be booked into the studio until at least January 1980, even assuming that the appropriate funding was secured. With the serial scheduled to begin transmission on January 19th, this effectively settled the matter. On December 10th, it was officially decided that The Horns Of Nimon would mark the end of a truncated Season Seventeen.

This turn of events brought an unhappy end to the tenures of both Graham Williams and Douglas Adams on Doctor Who. Production unit manager John Nathan-Turner, who had been trailing Williams since October, now became the programme's new producer. He was joined by Barry Letts, whom MacDonald had given a watching brief over Nathan-Turner in the newly-created position of executive producer.

John Nathan-Turner was eager to do away with 6-part stories like Shada

Although he was without a script editor, Nathan-Turner quickly began formulating his plans for Season Eighteen. In particular, he was eager to do away with six-part stories like Shada, which he felt were too long and overextended to hold viewers' interest. During November, Nathan-Turner had successfully obtained funding from Bill Cotton, BBC One's Controller of Programmes, for two extra episodes of Doctor Who. This meant that Season Eighteen would consist of seven four-part adventures, making it the longest run of Doctor Who since Season Six more than a decade earlier.

By this time, Nathan-Turner had met the acquaintance of diehard fan Ian Levine. Levine was a collector of old Doctor Who episodes, and gave the new producer access to his library. With Levine's encouragement, Nathan-Turner decided that Doctor Who should appeal more directly to its fanbase by mining its history for story ideas. He further concurred with Levine that the humorous approach favoured by Williams and Adams was rankling longtime viewers, and that Season Eighteen should target a more serious and mature audience.

Nathan-Turner had also become concerned with his regular cast of characters. He thought that the Doctor, Romana and K·9 formed too invulnerable a unit, making it difficult for writers to convincingly place them in danger, and for viewers to relate to them. During the production of Shada, he and Ward had discussed Romana's future on Doctor Who, and the actress had agreed that she would bow out partway through the eighteenth season. Now eager to pursue opportunities beyond Doctor Who, Ward was also unhappy with Nathan-Turner's plan to downplay the comedy elements that she and Baker preferred. Consequently, when Ward was contracted on January 16th, it was for only the first twenty episodes of the new season.

Nathan-Turner's search for a script editor initially led him to offer the post to Johnny Byrne. Nathan-Turner knew Byrne from his days as production unit manager on All Creatures Great And Small, to which Byrne had contributed several scripts. Byrne was not willing to move to London from his home in Norfolk, and declined the position. However, he did indicate his interest in developing a story idea for Doctor Who.

Instead, Shoestring producer Robert Banks Stewart -- who had written 1975's Terror Of The Zygons and 1976's The Seeds Of Doom -- recommended his former colleague Christopher H Bidmead. Nathan-Turner approached Bidmead in late December, only to find him dismissive of Doctor Who, which he felt had lately wallowed in fantasy instead of championing hard science. However, Bidmead was persuaded when Nathan-Turner and Letts convinced him that they shared the same concerns, and would be striving to ground Doctor Who more firmly in reality. Bidmead began working on Doctor Who soon after New Year's Day 1980.

Tom Baker and Lalla Ward agreed that their romance of the previous year had been ill-advised

On January 18th, Tom Baker was contracted for Season Eighteen. By this time, he and Ward had agreed that their romance of the previous year had been ill-advised, although they committed to maintaining an amicable working relationship. Meanwhile, David Brierley had approached Nathan-Turner about appearing on camera in a forthcoming serial, in addition to continuing his voicework as K·9. When Nathan-Turner refused to offer any such guarantee, Brierley informed him that he would not be returning to Doctor Who for a second season. Nathan-Turner then attempted to coax John Leeson back to the programme. Leeson was the original voice of K·9, and had left following Season Sixteen. With Nathan-Turner having decided that K·9's exit from Doctor Who was imminent, Leeson agreed to be a part of the robot dog's farewell episodes. He was contracted for an initial eight episodes on February 11th.

Through all of these changes, Nathan-Turner had not forgotten about Shada. On April 30th, the producer sent a revised set of scripts to Roberts, to seek the director's input on the idea of completing the serial in the form of two fifty-minute episodes to air over Christmas. This scheme was opposed by Bidmead, who felt that Shada was out of keeping with the more serious style that he and Nathan-Turner were implementing. Plans for this remounted version of Shada moved forward, and it was intended that a minimal cast would reunite for a pair of two-day studio blocks during October. By June 25th, however, Nathan-Turner had been forced to abandon the project when it turned out that the studio space was not available. Nonetheless, he arranged for the extant Shada material to be preserved within the BBC Archives for possible future use.

In 1983, an unofficial Shada compilation was prepared by Levine, with the assistance of fellow fans Richard Landen, James Russell and Kevin Davies. In addition to the completed location and studio material, they used printed text from the rehearsal scripts in place of the unfinished segments. This incarnation of Shada debuted on September 4th at the Panopticon 5 convention in Birmingham, West Midlands. The same year, two scenes from Shada were edited into The Five Doctors. Baker had declined to participate in the twentieth-anniversary special, and so Nathan-Turner elected to use brief clips from Shada in order to ensure that the Fourth Doctor was represented.

In 1984, Noel “Snowy” Lidiard-White of BBC Enterprises suggested to Nathan-Turner that Shada might be readied for release on video. At the time, the Doctor Who VHS range was still in its infancy, with the debut volume, Revenge Of The Cybermen, having been made available only the year before. In November 1985, Nathan-Turner mooted the possibility of having the Sixth Doctor, Colin Baker, fill in the missing material either with linking narration or in on-screen segments in which he would be telling the story of Shada to his companion, Peri, played by Nicola Bryant. Nothing came of these ideas, however.

Shada was released on video in 1992, bringing it to the public eye after more than 12 years

Finally, in 1991, BBC Video scored notable commercial success with a series of special Doctor Who releases overseen by Nathan-Turner. This prompted him to approach Tom Baker about recording linking narration for Shada. Baker agreed, on the condition that he would appear as himself and not as the Fourth Doctor. He recorded several short clips on February 4th, 1992, at the Doctor Who: Behind The Sofa exhibition at the Museum of the Moving Image in Lambeth, London. David Brierley returned to record the rest of K·9's dialogue and various special effects were also added or refined. The video was released on July 6th, finally bringing Shada to the public eye after a delay of more than twelve years.

Although Shada was now commercially available, there remained a desire for a version which dramatised the entire narrative. When Big Finish Productions began releasing original Doctor Who audio plays in 1999, one of producer Jason Haigh-Ellery's early ideas was an adaptation of Shada. This project gained traction with BBCi, the team responsible for the BBC's official Doctor Who website, who helped secure the necessary permissions from the estate of Douglas Adams. At the time, Tom Baker was not interested in working with Big Finish, so Shada was rewritten for Paul McGann, whose Eighth Doctor was the most recent to have appeared on television. Producer Gary Russell devised the notion that the events of The Five Doctors -- in which clips of Shada had appeared -- had changed time so that the Fourth Doctor's involvement in the adventure had been wiped from history. The Eighth Doctor would seek the help of Romana and K·9 to set things right.

Big Finish's version of Shada was recorded by director Nicholas Pegg between November 12th and 14th, 2002 at Christchurch Studios in Bristol. An entirely new cast was brought onto the project, with the sole exception of Ward as Romana; Leeson voiced K·9 on this occasion. The first episode of Shada premiered on the BBC Doctor Who website on May 2nd, 2003, as part of the festivities surrounding the programme's fortieth anniversary. The six episodes were then made available on a weekly basis, accompanied by limited animation featuring the artwork of Lee Sullivan.

In 2011, Levine privately funded animation to fill the gaps in the material recorded for Shada. With Tom Baker again declining to participate, he hired Paul Jones as the voice of the Fourth Doctor. Brierley had died in 2008, and so Leeson again provided the dialogue for K·9. Levine hoped to reach an agreement with BBC Worldwide to create a new commercial release of Shada on DVD, but this never materialised.

However, the notion of animating missing Doctor Who was gaining traction. In 2016, Patrick Troughton's debut adventure as the Second Doctor, 1966's The Power Of The Daleks, was released in this form, with all six of its episodes fully recreated. It was decided that a new, feature-length version of Shada should be prepared by director Charles Norton, mixing the existing live-action footage with animation and new special effects. Dialogue was recorded on June 9th and 13th, 2017 at Audio Sorcery Recording Studios in Tunbridge Wells, Kent. The material was edited to rely only on existing clips of Brierley and Denis Carey (who played Chronotis, and who had died in 1986). This time, Tom Baker not only agreed to provide the Doctor's voice, but also to film a special live-action coda, in character. It was recorded on September 13th, using a replica TARDIS set at IMG Studios in Uxbridge, London. This version of Shada was initially released as a digital download in November 2017.

• Doctor Who Magazine #267, 29th July 1998, “Archive: Shada” by Andrew Pixley, Marvel Comics UK Ltd.
• Doctor Who Magazine Special Edition #9, 22nd December 2004, “One Step Beyond” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #90, 2019, “Shada”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Handbook: The Fourth Doctor by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing.
• Doctor Who: The New Audio Adventures: The Inside Story by Benjamin Cook (2003), Big Finish Productions Ltd.
• Doctor Who: The Seventies by David J Howe, Mark Stammers and Stephen James Walker (1994), Virgin Publishing.
• In·Vision #44, June 1993, “Production” edited by Justin Richards and Peter Anghelides, Cybermark Services.