The first episode of Doctor Who—"An Unearthly Child"—was the story of a misfit pupil in an educational establishment, and her unlikely relationship with a charismatic old man. "The Pilot" (working title: "A Star In Her Eye") follows a similar arc in places, with nods to the Doctor's past, while showing a new side of his character, one that is less keen to run and keep running, and more interested in making a long-term home for himself, somewhere with lots of books and lots of blackboards. It is also the first time the Twelfth Doctor has introduced himself to a new companion, which casts new light on his idiosyncrasies and personality.

Here are a few things to keep an eye out for, the next time you watch:

As it's a tribute of sorts to the very early days of Doctor Who, it's fitting that the two romantic leads in the story should have the names Bill and Heather. William Hartnell, the First Doctor, was known as Bill or Billy, and Heather was the name of his wife of 46 years.

The First Doctor kept an identical Out of Order sign ready to hang on the TARDIS door. It was first seen in "The War Machines."

In the cellar where the Doctor has hidden his vault, there's a sign for (or from) the Mary Celeste. This famously deserted ship was part of a previous adventure in which the TARDIS was tracked across time and space. The First Doctor had to escape Daleks in time machines as part of "The Chase," and actually stopped off onboard the Mary Celeste on their way. The crew thought the Dalek they saw was a supernatural being called "the Barbary Terror" who had come to take their souls, and all jumped overboard.

[caption id="attachment_396516" align="aligncenter" width="1920"] Mary Celeste (Photo: BBC)[/caption]

There are two big nods to Douglas Adams in this story. The idea of a Time Lord taking up a post in a university for many years was part of the premise for his story "Shada," the filming of which was never completed. In Adams's story, Professor Chronitis spent years lecturing at the fictitious St. Cedd's College, Cambridge.

The second nod occurs during the Doctor's lecture, when he states that “time is an illusion,” which is the first part of a particularly Doctor-ish Zaphod Beeblebrox quote from Hitchhikers Guide to the Galaxy, the second half of which is "...lunchtime doubly so."

https://www.youtube.com/watch?v=oM4VPJJ4yrs

As the Doctor attempts to wipe Bill's memory, she asks that he imagine if someone tried to do it to him. Then, as the Doctor ponders on this, you can hear Murray Gold's "Clara's Theme", a musical nod to the Doctor's memory having been wiped of all trace of Clara Oswald in "Hell Bent."

Nardole's simplified explanation of the TARDIS's multi-dimensional interior echoes the way the Fourth Doctor used two boxes (and perspective) to show his companion Leela how a larger box could appear to fit inside a smaller one in "The Robots of Death": "If you could keep that [larger box] exactly that distance away and have it here, the large one would fit inside the small one."

https://www.youtube.com/watch?v=pvnKXOGYKM8

As well has having photographs of his granddaughter Susan and River Song on his desk, the Doctor's office contains Rembrandt van Rijn's Self Portrait with Two Circles, Joshua Reynold's Portrait of Emma Hart and George Romney's Lady Hamilton in a Straw Hat, and the bust of Ludwig van Beethoven he had in the TARDIS while explaining the Bootstrap Paradox in "Before the Flood."

The skirmish into which the Doctor takes Bill and Nardole is part of the war between the Daleks and the Movellans. This centuries-long conflict features as part of the Fourth Doctor story "Destiny of the Daleks".

[caption id="attachment_396514" align="aligncenter" width="996"] Sonics (Photo: BBC)[/caption]

The pen pot on the Doctor's desk appears to contain all of the sonic screwdrivers he's been seen using. The one with yellow-and-black stripes was the Third Doctor's, the tall one with a reddish silvery hoop was used by the Third and Fourth Doctors, while his Fourth and Fifth incarnations had the one with the red hoop at the top, as later used in this episode by Nardole.

The Seventh and Eighth Doctors had the silvery hooped sonic with the red gem at the top, and the Ninth and Tenth Doctors both used a sonic with a rounded blue gem on top, like a torch. The one used mostly by the Ninth Doctor burned out during "Smith and Jones" and was replaced with a similar, but slightly larger version. The Eleventh Doctor's sonic is, of course, the knobbly one at the back.

The War Doctor's sonic doesn't appear to be in the pen pot, nor does the blue gem sonic the Eighth Doctor is seen using on the cover of his Big Finish audio adventures. And while the stubby sonic first seen in the hands of the Second Doctor may well be in there somewhere, it's probably too short to be visible.

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