“Hell Bent” is episode twelve of season nine of the new Doctor Who and the season finale.
A the end of the previous episode, “Heaven Sent”, the Doctor had just spent several billion years inside his confession dial, where he refused to give up a final secret regarding the hybrid, before he finally exited on Gallifrey, outside the Citadel of the Time Lords (after dying multiple times; were those real deaths?). So, naturally, this episode opens in Nevada.
The Doctor walks into a roadside diner, where Clara is apparently working behind the counter. However, she doesn’t seem to recognise him. Nor he, her. He then tells her a story.
On Gallifrey, the Lord President of the High Council of the Time Lords is not happy to see the Doctor, and all the cloister bells are ringing. The Sisterhood of Karn is there, too, as Gallifrey is now almost at the very end of time.
The Time Lords are worried about the hybrid, and the Doctor claimed in the previous episode that it was him – although he never tells the Time Lords. It also seems that his entire sojourn in the confession dial was simply to try and set up a position where he can rescue Clara from her death in “Face the Raven”.
Not one of the most climactic season finales, which is probably to the good, as they were getting tricky to top. There’s also a nice, nostalgic look at a TARDIS interior in the white and roundels style of the original series.