The Marian Conspiracy ( audio story ) It was the first story to introduce a new companion for the Sixth Doctor : Evelyn Smythe played by Maggie Stables . This was 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 .