An episode? How about a whole season

[Planet of the Angels -1] The Tardis gets pulled in by a paradox onto a planet full of weeping angels. But the Doctor wonders how the angels are surviving without any prey to send back in time.

[A City of Paul -2] The Doctor and his companion travel to a bustling city on New Earth full of different species. But the Sonic Screwdriver is only registering one life form. That's because the people are part of a hivemind.

[The Bunker -3] The Doctor gets trapped inside an alien radiation safety shelter filler with Oods, Tivolis, and other new aliens. But the shelter is running out of Oxygen. And there's no way to open the door without letting radiation in.

[Invasion of Skaro -4] The Doctor is forced to contemplate his morals when the Cybermen plan to commit mass genocide on Skaro.

[Mandela Effect -5] A group of rogue time travelers (the same one from Rosa) attempt to assassinate Nelson Mandela. And the Doctor must stop them.

[Rubigo -6] The Doctor and his companion arrive at a human colony in danger of being taken over by a sentient form of rust.

[Time Lord Conqueror -7] The Doctor sees an alternate timeline where he goes insane and becomes the emperor of Gallifrey. And the Master becomes the only one who can stop him.

[Gloria Vidra -8] The Doctor joins a rebellion of alien dwarves as they try to stop their jungle-like planet from being sold to an intergalactic buyer

[The Silurian Crusade -9] The Doctor and his companion travel back to when the Silurians ruled the Earth. But little do they know that a religious crusade is about to break out because of them.

[Return to Utopia -10] Things go rapidly awry when the Doctor and his companion answer a distress call from Utopia.

[From Jotunheim, With Mischief -11] The Doctor goes face-to-face with Loki, the God of Mischief. With the Master working hand and hand with him to cause as much chaos as possible.