The Marian Conspiracy (audio story)

 was the sixth story in Big Finish's monthly range. It was written by Jacqueline Rayner, featured Colin Baker as the Sixth Doctor and introduced Maggie Stables as companion, Evelyn Smythe, the first companion original to audio to be created by Big Finish.

Publisher's summary
Tracking a nexus point in time, the Doctor meets Dr Evelyn Smythe, a history lecturer whose own history seems to be rapidly vanishing.

The Doctor must travel back to Tudor times to stabilise the nexus and save Evelyn's life. But there he meets the Queen of England and must use all his skills of diplomacy to avoid ending up on the headman's block...

Plot
Dr Evelyn Smythe's lecture on Tudor history is disrupted by the Sixth Doctor, whose noisy device reveals that she is part of a "temporal nexus point" — a potentially catastrophic change in established history. This is evidenced by the fact that Evelyn claims descent from John Whiteside-Smith, a man who served Queen Elizabeth I and whose father was executed by Queen Mary for treason — and whom the Doctor insists never existed. Dr Smythe is forced to take the Doctor seriously when he comes to her home and they discover that half her family tree is vanishing from her records, and she may very well cease to exist. When the Doctor says he will travel back in time to the court of Queen Elizabeth to fix the problem, Evelyn insists on accompanying him.

The TARDIS traces the origin of the nexus point and lands in 16th century London. The Doctor goes to court, while Evelyn — wearing a device of the Doctor's making to prevent her from fading in and out of existence — heads to a local alehouse, hoping to learn about history first hand. Both time travellers assume Elizabeth is on the throne, but they're wrong — it's 1555, Mary is still on the throne, and Elizabeth is still imprisoned. Evelyn gets herself in trouble loudly toasting Elizabeth by mistake, while the Doctor — using his usual John Smith alias — finds himself brought by Queen Mary's handmaiden, Lady Sarah, to attend to the Queen's health.

Luckily for Evelyn the men she is drinking with — George Crow and young William Leaf — are Protestants, unhappy about Mary's heresy laws, and take her outside the pub to safety. They meet with the Reverend Thomas, who reprimands Crow and Leaf for revealing themselves to Evelyn, whom he believes may be a Catholic spy.

At court, the Doctor converses with Queen Mary, finding favour by offering an independent opinion — something she regrets is lacking in the courtiers who surround her. He tries to explain how history will see her for her brutal treatment of Protestants, but Mary will not be swayed, as she believes she is doing what is right. She keeps him around as she speaks with Francois de Noallies, Bishop of Aix, who tries to persuade Mary to reconcile with Elizabeth — which, as the Doctor helps Mary see, is clearly a ploy to help prevent England siding with Spain in war against the French. The Queen rejects his idea, and the Doctor escorts him out, telling him he wastes his time with plots to put Elizabeth on the throne. He then speaks with Sarah, asking her to send a messenger to find Evelyn.

Evelyn has been questioned by the Reverend Thomas, and she realises he is plotting against Mary. She tries to dissuade him, knowing that no rebellion succeeds and that Mary will die of natural causes, but he is resolute, and will not flee the country leaving other Protestants of lesser means to die. Evelyn tries to convince him to bide his time, explaining that Mary will die and that she is not truly pregnant — something of great interest to the Reverend.

When Leaf and Crow return from scouting confirming that no-one is watching them, Evelyn makes cocoa for her new Protestant friends. This leads to questions about the content of her bag, including a bottle of prescription analgesics which she cautions them not to take, as they could prove fatal in too high a dose. Crow, disliking the cocoa, heads to the alehouse for beer — but soon returns claiming an urgent message has arrived from court for Evelyn. Assuming the Doctor is in peril, Evelyn rushes off, accompanied by Leaf. After she's gone, de Noallies arrives to speak with Reverend Thomas — they are in league against Mary. The Bishop tells the Reverend about the Doctor, who seems set against their plot, and the Reverend sees this as proof that Evelyn is a traitor — and realises how he can discredit her.

On her way to court, Evelyn begins once more to fade in and out of existence — she left the Doctor's stabilisation device behind in her bag. The Reverend soon appears, with Evelyn's bag, and she returns it stability, but the Reverend's motives are not pure: he wants her to be carrying her bag when she meets with Mary, who is so afraid of plots against her life.

While Queen Mary rests, the Doctor muses that she is not what he expected, and discusses public opinion of her with Sarah. Sarah thinks the public are indifferent, but she herself is passionate about one thing: Mary repealed laws that allowed Protestant clergymen to marry. They also discuss whether doing what you feel is right makes you a good person, even if it means the deaths of others. Evelyn arrives, and she and the Doctor visit the Queen, but almost immediately de Noallies bursts in to accuse Evelyn of plotting to kill Mary with the "poison" in her bag — the analgesics. Evelyn realises Reverend Thomas has betrayed her, but the Doctor explains that the pills are medicine and quite safe in small doses, and gives some to Mary, which help with her pains. de Noallies returns to the Reverend and berates him for the failure of his plan, but this only spurs Thomas to take more direct action. He meets with a conspirator, supplying a potion and insisting only a few drops of it are used, but has to flee when Mary's guards arrive to arrest him — she heard Evelyn mention his name. He seeks refuge with de Noallies, but the Bishop refuses to help him.

Meanwhile the Doctor is dismayed that Evelyn has given too many hints to the Reverend Thomas; she is horrified to realise that Thomas would have never tried to murder a pregnant woman — but thanks to her, he knows Mary isn't truly pregnant! Crow arrives and confirms their fears, too frightened to take part in a plot to murder the Queen, but uncertain how Thomas intends to carry out his scheme, except that he has an ally at court. They suspect de Noallies, but have no idea what the plan is. One other thing may have become clear, though: the Queen has decided to reward the Doctor by marrying him to Lady Sarah, who Leaf and Crow reveal is Sarah Whiteside. If the Doctor marries her, then surely their child will be Evelyn's ancestor, John Whiteside-Smith — making the Doctor the father who will be executed by Mary!

This seems to be coming true when Mary's guards arrive and arrest the company, who have been named as co-conspirators by the captured Reverend Thomas. Imprisoned in the Tower, the Doctor and Evelyn realise they must escape and prevent the plot against Mary, or history will be altered. Trying to work out Thomas' plot from what they know about him, they guess that de Noallies will poison the sacraments at the Queen's next Mass. They manage to escape from the Tower, mostly thanks to Evelyn, and travel down the Thames to the Palace. There they are prevented from entering the Queen's presence during her Mass by Sarah Whiteside, since such sacrilege would lead to excommunication, and the Doctor realises no holy man of any faith would poison the sacraments. As de Noallies and Mary emerge, the Doctor realises that Sarah is Thomas' co-conspirator: Thomas' last name is Smith, and Sarah was upset at Mary's changes to the laws because it discredited her marriage to him. She was to feed drops of poison to the Queen, though Thomas told her it was a potion that would give her dreams to show her the error of her ways. Playing on Sarah's duty to her husband, and also deducing the Lady is pregnant with Evelyn's ancestor, the Doctor dissuades Mary from executing Sarah, and she is sent into Elizabeth's service instead; she thanks the Doctor by saying she will name her son after him. Thomas, however, is not so lucky; the Queen offers to spare him if he will recant his Protestant faith, but he refuses, and so goes to the stake to be burned.

History appears to be back on track, even as the Doctor laments Mary's lot, but Evelyn insists that they at least save Leaf and Crow, who are still stuck in the tower awaiting execution. They use the TARDIS to fetch them, and to transport them — and Crow's family — to a safe Protestant city. Afterwards, as they discuss their adventure, the Doctor is surprised by Evelyn, who insists she will continue to travel with him — after all, she can hardly turn down the opportunity to see history firsthand, even if she has discovered her ancestors were a bit of a disappointment.

Cast

 * The Doctor - Colin Baker
 * Dr Evelyn Smythe - Maggie Stables
 * Reverend Thomas Smith - Nicholas Pegg
 * The Queen - Anah Ruddin
 * Lady Sarah - Jo Castleton
 * Francois de Noailles - Barnaby Edwards
 * George Crow - Sean Jackson
 * John Wilson - Gary Russell
 * William Leaf - Jez Fielder
 * Royal Guard - Alistair Lock

Music

 * Evelyn hums The Blue Danube.

Foods and beverages

 * The Doctor agrees to take Evelyn to Mexico or Havana to pick up some chocolate with which to make a chocolate cake.
 * Evelyn gives Mary some aspirin; she takes them with beer.

The Doctor

 * The Doctor once again uses his well worn alias, Dr John Smith, to gain access to the Queen's inner circle.
 * The Doctor mentions meetings with Socrates, Sir Francis Drake, Henry VIII, Lady Jane Grey (whom he met in the Tower of London), William Cecil and Queen Elizabeth I.

Individuals

 * Evelyn has a pathological love of cocoa and cakes.
 * Evelyn tells the Doctor that the class of 1974 were "particularly unattractive."

Continuity

 * When viewing London in 1555 in the TARDIS scanner, Evelyn muses that it will all be burnt down in the Great Fire of London in September 1666, a statement that causes an embarrassed intake of breath from the Doctor. His fifth incarnation played a major role in starting that fire in TV: The Visitation. Ironically, the Fourth Doctor, arriving shortly before his future self's departure, was wrongfully accused of starting the fire only hours later. (TV: Pyramids of Mars, PROSE: The Republican's Story) A similar exchange occurred between the Doctor and Peri Brown in AUDIO: Point of Entry.
 * The Doctor says that he should "pop back and support Darwin." He and Evelyn would later meet Charles Darwin on the Galápagos Islands on 19 September 1835. (AUDIO: Bloodtide)
 * Both the First and the Third Doctors referred to being imprisoned in the Tower of London. (TV: The Sensorites, TV: The Mind of Evil) The Fifth Doctor and Nyssa suffered the same fate in the late 17th century, charges of forgery having been levelled against them by Sir Isaac Newton. (AUDIO: Summer) The Sixth Doctor was also briefly imprisoned in the Tower in 1590. (AUDIO: Point of Entry) The War Doctor, the Tenth Doctor, and the Eleventh Doctor would later be imprisoned in the Tower together by Mary's sister Elizabeth I. (TV: The Day of the Doctor) Evelyn and the Sixth Doctor would return to the Tower in an alternative 2003 (AUDIO: Jubilee) and 2010. (The Crimes of Thomas Brewster) In the former case, Evelyn learned that alternative versions of herself and the Doctor were imprisoned together in the Tower for decades before her counterpart died. She briefly met the alternative Doctor, who had been rendered practically insane by decades of isolation during the latter part of his hundred years as a prisoner of the English Empire. She chose not to tell the Doctor that she had met his counterpart. (AUDIO: Jubilee)
 * The Doctor tells Evelyn that the last time that he was in the Tower, he was visiting Lady Jane Grey. (PROSE: The Nine-Day Queen)
 * The Sixth Doctor previously visited 16th century London at least twice, both times in the company of Peri Brown. (AUDIO: Point of Entry, Recorded Time)
 * Queen Mary refers to her late stepmother, Anne Boleyn, the mother of her younger half-sister Elizabeth, as a "harlot." Earlier in his personal timeline, the Doctor and Peri met Boleyn on 4 May 1536, shortly before her execution. (AUDIO: Recorded Time)
 * The Doctor tells Lady Sarah that he once destroyed an entire race. (TV: Terror of the Vervoids)
 * The Doctor and Evelyn would eventually visit Queen Elizabeth's court at some point before she departed the TARDIS. (AUDIO: Thicker Than Water) Later in his personal timeline, the Doctor met her on at least four further occasions. (AUDIO: Terror Firma; TV: The Shakespeare Code, The End of Time, The Day of the Doctor)
 * The Doctor refers to the fact that people have died while travelling with him. (TV: The Daleks' Master Plan, Earthshock; AUDIO: The First Wave)
 * Evelyn speaks very highly of Elizabeth as independent and putting country and duty above all else; ironically, Elizabeth would eventually wed the Tenth Doctor. (TV: The Day of the Doctor)