Twitter is freaking out over that big reveal in the season premiere of Doctor Who

What better way to ring in a new year and a new decade than with a new episode of Doctor Who? The Season 12 premiere for the venerable series just aired, and shockingly, the Internet has some thoughts.

***WARNING! The following contains major spoilers for the season premiere of Doctor Who!***

In tonight's episode, "Spyfall," the first of a two-parter written by showrunner Chris Chibnall, intelligence agents are under attack from alien forces, so MI6 turns to The Doctor and her friends to (once again) save the world. "Spyfall" marked the return of Jodie Whittaker as the mercurial 13th Doctor and her friends, Graham, Ryan, and Yaz, played by Bradley Walsh, Tosin Cole, and Mandip Gill, respectively. It also featured guest appearances from Stephen Fry and Sir Lenny Henry.

But more importantly, it featured a stunning cliffhanger and the return of an old foe few of us expected ... The Doctor's fellow Time Lord nemesis, The Master (sometimes also known as Missy). Not surprisingly, Twitter is freaking out. Fortunately, folks seem to be losing their minds in a good way over tonight's big reveal. (Some tweets contain NSFW language.)

The second part of "Spyfall" airs Sunday, Jan. 5.

While the previous season consisted entirely of standalone stories, Chibnall has revealed that this season will feature more two-part stories and a season-long arc. Season 12 also marks the return of a few familiar (alien and robot) faces, as demonstrated by tonight's episode.

New episodes of the 12th season of Doctor Who air each Sunday at 8 p.m. EST on BBC America. Happy 2020, nerds!