Turns out the Great Intelligence is the Yeti of this story.
After over a hundred episodes, we finally encounter “The Yeti of the Story”! Or do we?
Troughton’s Second Doctor, accompanied by Jamie and Victoria, arrives in 1930s Tibet, where apparently he’s been before. Yep, allegedly he had quite the adventure there some 300 years earlier. We don’t learn anything more about that, though.
Yeti, or so they’d have us believe, are roaming the Himalayas, harassing the nearby Det-Sen monastery, and Doc & Co decide to intervene. Because why wouldn’t they?!
It turns out, however, that this is not just some natural occurrence. In fact, it’s the very first appearance of one of The Doctor’s most legendary foes – a foe who will reappear in both Classic Who and New Who…