While little is known beyond the title, we now do know that Ryan, Graham, and Yaz will return. Chibnall doesn't know when the episode will air but it'll be some time between Christmas and New Year.
Showrunner Chris Chibnall said:
“We can’t leave the Doctor there! On that cliffhanger! Well, we did. But rest assured, the Doctor and her friends will be back for a one-off extended Special around Christmas and New Year. (I don’t know when they’re going to put it on yet, otherwise we’d tell you!). There will be Daleks. There will be exterminations. Thrills, laughter, tears. You know. The usual. See you at the end of the year.”
Showrunner Chris Chibnall said:
“We can’t leave the Doctor there! On that cliffhanger! Well, we did. But rest assured, the Doctor and her friends will be back for a one-off extended Special around Christmas and New Year. (I don’t know when they’re going to put it on yet, otherwise we’d tell you!). There will be Daleks. There will be exterminations. Thrills, laughter, tears. You know. The usual. See you at the end of the year.”