The World Tree (audio story)

 was a special free release in the Short Trips audio range from Big Finish Productions series. It was the winning entry in The Paul Spragg Memorial Short Trip Opportunity. It is notable for being one of the first works of fiction implied to feature the Fifteenth Doctor.

Publisher's summary
Nora Wicker is forgetful. Not big things - not yet, anyway. She remembers her address and where the shops are. She remembers people when they come to visit, no matter how rare that is.

But she doesn't remember where the bush with the red leaves in her garden came from - and she definitely doesn't remember asking for a house call from the Eleventh Doctor.

Plot
It is Wednesday 19 August 1987, and 76-year-old Nora Wicker looks out of her kitchen window into her garden, concerned. She spots a twisted red bush in the middle of her beloved flowers and cannot remember planting it; although she is near-certain it is new, she has no way of knowing for sure, as the hospital has told her that her memory is failing. She tests herself by recounting the date, her birth date, and her husband Ernie's birth and death dates, but stops herself before she gets too upset.

As she clears up her breakfast, however, Nora is distracted by something else: a young man in her garden, pointing a glowing metal tube at the red bush and talking to himself. Upon being caught, he cheerily introduces himself as the Doctor, which makes Nora assume he is with her surgery - a flash of his psychic paper seemingly confirming his medical degree.

Allowing him inside, Nora brings tea and biscuits, but the Doctor is more interested in scanning everything with the sonic screwdriver. After confirming some good news and settling down, Nora voices her suspicions that the Doctor is with her surgery and is even there at all, noting that her squeaky garden gate made no noise when he appeared and he has not affected the wobbly kitchen table upon sitting down. She proves her point by throwing an apple directly through his chest, causing him to beam that she always figures it out every time, no matter what he does. He explains that although he is real, he is simply a soft-light hologram being beamed to her from the moon of Vega, 4.2 million light years away. Nora then catches up to the Doctor's mention of having done this before, and he explains that he first met her "today, 46 years ago", confusing her even further.

The Doctor tries to explain that his visit is related to interstellar botany: a tiny seed floated through space for a thousand years before happening by chance to land in Nora's garden that morning, sprouting into the red bush. However, as she looks at it again, she is astonished to see it is no longer just a bush, but a five-foot-tall tree. As she rushes outside to investigate, the Doctor describes the plant as a miracle, and although Nora dismisses this, he retorts that she should not let it hear that, as it has already started listening. He describes it as a World Tree, which lives for tens of thousands of years and absorbs all the knowledge and stories of the billions that interact with it. However, he adds that its extremely fast growing will only get faster - by the end of the day it will be the biggest tree on Earth and will keep going until within a month, the planet will be torn in two by the size of its roots, unless someone controls it. This, the Doctor explains, is his job, although he still needs to deal with the problem of Nora.

Some time later, Nora asks the Doctor to explain the situation again in simpler terms. He describes how he had to find some way to keep the World Tree's growth under control while the Grand Arboretum find a new planet for it, and as it was not safe to transport it naturally, it had to be frozen in a Time Bubble instead, from which nothing can get in or out. While time progresses naturally outside, on the inside time is rewound 24 hours every midnight, resetting everything... including Nora, whose house has been caught by the Doctor in the bubble too. The Doctor reveals that she has relived the events of 19 August 1987 no fewer than 16,920 previous times - the equivalent of just over 46 years. She gets angry at his assertion that she is better off forgetting all her previous days in the time loop, but he insists that he has finally found a solution: if his sonic screwdriver activates in sync with his future self outside of the Time Bubble, it will open just enough to allow Nora out, upon which she can be returned to 1987 in his TARDIS. The Doctor smiles and tells Nora that she is going home.

With the evening setting, Nora and the Doctor sit in her garden, having spent most of the day talking about their lives and stories. Nora questions why the Doctor keeps coming back to her in each time loop, as he could just let her out one day and she would be none the wiser, but he admits to being fascinated by her life and now considers her an old friend. As they talk, they are interrupted by the appearance of the TARDIS outside of the Time Bubble. The Doctor's future self steps out, a "dark figure" blurred by the bubble, and the two Doctors begin to sync up their sonics to let Nora out. However, seconds before the plan concludes, Nora proclaims that she does not want to go. This split-second of hesitation on the Eleventh Doctor's part causes the sync to go wrong; his sonic screwdriver overloads and the other Doctor, realising they cannot enact the plan after this, leaves in the TARDIS once more.

Although the Doctor is somewhat annoyed that the solution to his problem has been spoilt, Nora insists that she wishes to stay - although the World Tree would still only technically be one day old when it is finally collected by the Grand Arboretum, she cannot bear the thought that its first memories would be of it being scared and alone. She adds that, as someone whose memory is failing her, she knows how vital memories are, and would be happy to keep on reliving a good day where she has been fully lucid, which is getting increasingly rare. The Doctor understands and decides to leave a recording of his hologram with her so every day plays out the same way, promising that when the Grand Arboretum finally arrive, he will be with them to see her again, even if he has changed by then. With her mind made up, even for potentially thousands of years, the Doctor promises to see Nora tomorrow, "whenever tomorrow happens to be".

As the evening sun sets, Nora sits on the bench in her garden under the shade of the World Tree. She smiles at the thought that Ernie would have loved to have met the Doctor. She considers her meeting to be something of a fairy tale and, knowing that the young tree is listening, decides to tell it a story of her own before it heads into the stars: "It's about a man named Ernie Wicker - the handsomest man I ever saw in my life..."

Characters

 * Nora Wicker
 * Eleventh Doctor
 * Fifteenth Doctor

Worldbuilding

 * Nora was born on 24 May 1911 and is five feet and three inches tall. Her husband Ernie was born on 7 January 1908 and died in 1977.
 * Nora's regular doctor is named Dr Franklin. She has another short and bald doctor whose name she has forgotten.
 * Nora is a fan of Gardeners' World and especially Percy Thrower but notes that he has not been on TV in ten years.
 * The Doctor mentions Blinovitch and star whales in passing.
 * The Grand Arboretum is ruled by a Chief Gardener who is currently an Aplan.
 * Nora's house is in a Time Bubble, which the Doctor likens to Groundhog Day. Nora has not heard of it due to it not having been released yet.
 * Nora admits that, without family to visit her, the only way she can tell days apart is by listening to The Archers.
 * Nora has been stuck in the time loop of 19 August 1987 for 16,921 days, meaning it is 16 December 2033 outside the Time Bubble when the Doctor visits on this occasion.
 * The Doctor mentions that his sonic screwdriver is good at reversing polarities.
 * The Doctor claims to have played Scrabble against Samuel Johnson, calling him a "terrible cheat".
 * The Fifteenth Doctor waves to the Eleventh Doctor and Nora from outside the bubble.

Continuity

 * The Eleventh Doctor tells Nora that the Fifteenth Doctor's sonic screwdriver is the same as his, evoking the "same software, different case" line from.