Disclaimer: I am not J.K. Rowling. I do not own Harry Potter. I am not anything to do with the BBC either. I do not own Doctor Who.

Note: The following one-shot is a crossover, where the 'First Doctor' shows up at Hogwarts during the 1974-1975 school year. Hogwarts is assumed to be in an obscure corner/pocket-universe of the regular Doctor Who reality, on a 'parallel Earth' where magic works. This parallel Earth is assumed sufficiently 'off the beaten track' that the Tardis was seriously damaged in arriving/landing there.

Further Note: During the days of the First Doctor, the Tardis was referred to as 'The Ship' at times, and I think (although my memory may be faulty on this count, as it's been a while since I read those stories) that the First Doctor at times hinted that he had actually invented/built it.

Rating: This story is rated 'T'.


"Do you know why I have called you here, Mr. Snape?" the white haired slightly curmudgeonly old man who was Hogwarts' astronomy instructor this year asked the dark haired fourth year pupil?

"No sir." the pupil's eyes, which had been roaming around the chamber, taking in the various orreries, astrolabes, star-charts, telescopes, and the mysterious blue cabinet identified by lettering on it as a 'POLICE PUBLIC CALL BOX' in one corner, snapped back to his professor.

"The Evans girl. You helped her with her essay on orbits and calculus. Why?"

"She comes from the same town as me. And she's my friend."

"You may believe, Mr. Snape, that she is your friend, but I do not believe that she sees you in an equivalent light." the teacher's voice was harsh. "Still:" he acknowledged, unbending a little, "I understand a desire to cooperate with a fellow-creature who shares one's place of origin." And now he chuckled. "And I should not to be too harsh, if I have acquired a young assistant who wishes to try to help me spread the language of mathematics, to even one of his fellow pupils. The state of affairs, with regard to the instruction of even the simplest of mathematical concepts, appears to have been lamentable at this school of late, prior to the date of my arrival."

There was a long silence, whilst teacher and pupil studied one another.

"You have a question, Mr. Snape?" the teacher asked at last.

"Several, sir. Some of them about black-holes and supernovae and what is beyond the sight of our telescopes at the edge of our solar system? But why are you so interested in me sir? Do you want to recruit me to do something, after I leave Hogwarts? Or… before then?"

"No, Mr. Snape. I am interested in you, because you have one of the keenest intellects amongst the pupils at this school, and because you are prepared to think outside of the narrow confines of the textbook and to explore or innovate. Your astronomy essays are generally much more interesting for me to read and mark than those of your contemporaries, your answers to questions in my class show that you are usually amongst the first in your year to grasp a new concept which I have just presented, and you are capable of reasoning in a logical fashion. If you do not allow yourself to become drawn into the games of those interested in more temporal power – or to be distracted by the little mindedness of bigots who use the colours of a house tie as an excuse to attempt to humiliate others – I think that you have a great potential career ahead of you, as a scientist or an inventor. And it delights me, to be able to see and encourage that in a young man."

There was another silence, as they both considered what had just been said, weighing it carefully.

Then, a change of direction:

"What's that blue box in the corner, sir?"

"Ah: Now that is my greatest work, a truly miraculous travelling device, if you can believe it. Ordinarily, the interior is much larger than the exterior – the mechanism is difficult to explain, but not that dissimilar, in general effect, to a kind of extension charm – but my arrival here caused some damage to it, and it is currently awaiting repair. My travelling companions, who arrived here with me, are away working with Nicolas Flamel on manufacturing components which will allow us to resume our travels at the end of the school year. The actual equipment needed should be ready some months before that, but having committed myself to this teaching position here at Hogwarts, it would be unconscionable of me not to see the academic year out and to leave you and headmaster Dumbledore in the lurch. I wish that I could demonstrate some of its properties to you – but at the moment, in its current state, that is quite out of the question. Perhaps once it is functional again…"


It was a short while after the trip of the Doctor and his companions to the somewhat bizarre reality occupied by Hogwarts – and he, the Ship, and its crew were now back in much more familiar waters, so to speak .

"What are you doing, grandfather?" Susan asked, peering past the Doctor as his fingers flickered over a keyboard, his gaze fixed firmly on a screen.

"Hmm. Neville Longbottom and the Philosopher's Stone." he said to himself as much as to her. "Just checking some things on the Ship's database, my dear. First in the Neville Longbottom series by a well known late twentieth century Earth author." His fingers flickered again. "Severus Snape: minor character mentioned by Remus Lupin on a couple of occasions as someone that he and his friends bullied whilst at school, which actions Remus Lupin subsequently came to regret. Indicated to have left magical Britain after graduation. Fate unknown." He frowned. "I wonder… I wonder, very much, if we made some kind of a difference?"

"Well there was that business Ian and Barbara and I had to help Mr. Flamel with, whilst you were off teaching." Susan said. "That thing with the Grindelwald supporters who wanted elixir of life to restore their inspirational leader. We handled that entirely without any help from you."

"A mere bagatelle, my dear; Gellert would never have let himself be used as they wanted, given his relationship with Albus Dumbledore. But don't tell the others I said that. No. I have a feeling that I may have impacted events, much more than your heroics, but I cannot for the life of me remember what was supposed to have otherwise happened…"


Author Notes:

I wanted to give writing a Doctor Who/Harry Potter crossover a go, since a number of other writers have done them; the idea of a short piece where the First Doctor as a teacher to Severus Snape caught my imagination since it seemed to me that there were elements of their characters that were similar, and that they might see and respect something in one another, even separated by a gulf of years and by coming from different universes (and where Severus' has an additional set of 'rules' for something called 'magic').

I could see the First Doctor at Hogwarts in the role of an astronomy teacher - astronomy being a subject which doesn't require him to use much (if any) magic, and which does play to his strong scientific knowledge.

Ian Chesterton/Barbara Wright/Susan Foreman are all 'off scene' whilst the Doctor is at Hogwarts, making whatever replacement parts it is that will get the Tardis up and running again, and get them back to their home universe.

The events the Doctor was involved in turning out to be peripheral to a fictional series published back in the Doctor's 'main universe' is a bit cheeky of me. At any rate, though, with Severus Snape disappeared from the Wizarding scene after he finishes his Hogwarts career (Severus departing to work as a scientist/inventor somewhere else, presumably) events are assumed to have been thrown sufficiently out-of-whack with Harry Potter canon that Neville Longbottom ends up as The-Boy-Who-Lived; James is assumed to have married Lily but either the entire Potter family was massacred in this timeline (no Severus in the Death Eaters to beg Voldemort to spare Lily) or there was no prophecy like the canon one and Voldemort ignored the Potters altogether.

This story is a one-shot.