WARNING: The following contains major spoilers for the latest episode of Doctor Who, “Asension of the Cybermen,” which premiered Sunday on BBC.
"Ascension of the Cybermen" is the penultimate episode of Season 12 of Doctor Who, and the first episode of a two-part finale. But really, the episode closely follows the events of the series' previous entry, "The Haunting of Villa Diodati," which featured the prophesied arrival of the Lone Cyberman. After getting his metal hands on the Cyberium, the Lone Cyberman left the year 1816 to travel to the future, where it planned on bringing back the Cyber Empire to its former glory.
Now, in "Ascension of the Cybermen," all threads from Season 12 appear to converge. The episode takes us to the final days of the Cyber Wars and features humanity's last, desperate attempt at surviving the murderous robotic lifeforms. But the big surprise arrives near the end of the episode when, amid the chaos, Sasha Dhawan's villainous Master makes his long-awaited return.
"Ascension of the Cybermen" continues to pay off Jack Harkness' warning from "Fugitive of the Judoon," where the time-traveler advised the Doctor's companions not to give the Lone Cyberman what it wanted. However, what no one expected is for this to tie back to the events of the Season 12 premiere. In "Spyfall," the Doctor's nemesis, the Master, returned with a new face, once again hellbent on death and destruction. Worse yet, he brought with him new secrets that tied back to the very foundation of Gallifrey.
The Doctor eventually defeated her enemy and left him trapped in the dimension the Kasaavin hailed from. Now, the Master has returned. But how does all this tie to the Cyber Wars?
In the latest episode, the Doctor is on the trail of the Lone Cyberman. She finds him in the future during the last days of the Cyber Wars between humanity and the Cybermen Empire. Both sides have suffered catastrophic losses, and both sides' numbers have dwindled significantly. There are only a handful of Cybermen and humans left, and the latter are desperate to find a safe place where they can be free of the invaders forever.
This place is known as the Boundary, and it can be found on a faraway planet named Ko Sharmus. Once the Doctor eventually gets there, however, she finds that the Boundary is actually a mysterious portal -- a gate that, somehow, leads back to the ruins of Gallifrey, her homeworld. However, before she can cross over, the destroyer of the Time Lords, the Master himself, comes through the portal, setting foot on Ko Sharmus.
Obviously, the Doctor is taken aback by the whole thing. The portal to Gallifrey is surprising enough, but the Master's return just makes this situation all the more dire. What is the Boundary, really? And how did the Master escape the Kasaavin, only to find the Doctor in the future, at the end of the Cyber Wars? "Ascension of the Cybermen" brings forth plenty of new questions, but the Master promises answers. We may not know where everything will lead yet in next week's finale, but it appears all of this will bring Season 12 full circle.
Doctor Who stars Jodie Whittaker as the 13th iteration of the titular Time Lord. Whittaker is joined by co-stars Bradley Walsh, Tosin Cole and Mandip Gill in a series spearheaded by showrunner Chris Chibnall. The season finale is set to air on the BBC on March 1. The new season and all previous 11 seasons will stream on HBO Max later this year.