Sublime

There’s one overriding desire – to survive and prosper – yet each episode contains its own sub-goal

Moffat and Gatiss are implicated in both these enterprises, having built careers as TV authors out of fan fiction on television and literature,

In the wise words of Carson, the butler of Downton Abbey, “The business of life is the acquisition of memories. In the end that’s all there is.”

in the climax, they apply them.

Like all good crisis points, it’s a subversion of expectation, a cliffhanger, an antithesis to what’s gone before.

this is drama; every action has a consequence.

Good structure will deliver a crisis point that forces the protagonist to choose between their old and new selves.