Doctor Who: All 40 Steven Moffat Episodes Ranked From Worst To Best

A foreboding momentum builder that pays off in the most mind-boggling and jaw-dropping way.

Right, may as well put a twist on the heavily-referenced souffle metaphor to describe this "foreboding momentum builder". First, take a chained up serial killer whose creepy inane ramblings actually translate as vital information about the Doctor. Allow the serial killer a stay of execution.

Take a handful of nightmarish-looking yet handily slow moving Whisper Men who, er, whisper sinister nothings and murder Jenny (don't worry at this point because she does rise again). Sprinkle a Sontaran for light relief.

Now things start to get cooking with a visibly distressed Doctor and a plummet down to a godforsaken planet that makes the Tower of Terror feel like a gentle elevator ride. The desolate world bears resemblance to the plateau of Gorgoroth and Morpheus' "desert of the real" revelation to Neo.

Now a physical embodiment of the Great Intelligence, Richard E. Grant is a more threatening face grabbing and face-ripping villain this time around.

Moffat is a bloody clever writer - sometimes too clever for his own good, as we infuriatingly know. But here, he deftly uses his go-to character in River Song to successfully navigate the obvious red herring, i.e. the title of this episode. Also satisfactorily solve the puzzle (he does love a girl with a mystery) of why the Doctor kept bumping into different versions of Clara.

And then of course, it turns out the clue really was in the title when the Doctor castigates his darkest secret.