BBC has just released the official trailer for Doctor Who: The Power of the Doctor, this special is to mark 100 years of British Broadcasting. In, this article, there is a quick trailer breakdown about what we’ve spotted and the official synopsis that’s been released.
Official synopsis
In this feature-length special to mark her last adventure, Jodie Whittaker’s Thirteenth Doctor must fight for her very existence, against her deadliest enemies: the Daleks, the Cybermen and her arch-nemesis, the Master.
Who is attacking a speeding bullet train on the edges of a distant galaxy? Why are seismologists going missing from 21st century Earth? Who is defacing some of history’s most iconic paintings? Why is a Dalek trying to make contact with the Doctor? And just what hold does the mesmeric Rasputin have over Tsar Nicholas in 1916 Russia?The Doctor faces multiple threats…and a battle to the death.
Trailer breakdown
Rasputin

The Master (Sascha Dhawan) is back at it again with his antics, this time he is posing as Rasputin in time. His plan remains to be strategic and conniving as he is hell-bent on going after The Doctor, in order to ‘erase’ her from the timeline.
Dalek Incursion

Inston-Vee Vinder, Yaz, Dan and The Doctor combine all of their efforts one last time in order to fight back a full-scale Dalek incursion, as the Daleks threaten that it is imminent.
There’s TWO of them?!
There are two TARDIS boxes spotted at the bottom of the image. Could this be another Doctor from a different dimension, a Doctor from another time, or the masters TARDIS? There seems to be some heat beam hitting the TARDIS force-sheild here too.

This could indicate further that this is actually the Masters TARDIS and he changed the Chameleon Circuit to make his also look like a Police Public Call Box; to make a mockery or trick her companions or The Doctor.

Ace and Tegan

Ace and Tegan are helping Kate Steward and The Doctor to investigate missing paintings and seismologists and they can also be seen taking on the Lone Cyberman, also known as Ashad. He’s brought other Cybermen as reinforcements.
Earth under attack
The planet is under a massive attack by another planet size killing invasion, almost like a super-heated death star from Star Wars. There are also two Earths colliding!
Regeneration

Jodie Whittaker’s regeneration can be seen at the end as she appears in distress calling for Yaz. It’s safe to say that Yaz survives by the end of this episode.
Official trailer
Check out the official trailer here:
Air date and time
Doctor Who: The Power of the Doctor will air on October 23, at 7:30pm.