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

Now that we've become well-acquainted with River Song in a wibbly-wobbly, timey-wimey fashion, it gives this two-parter added poignancy on rewatching it.

It's those certain moments (spoilers) throughout that make you knowingly smile but is also coupled with tinges of sadness; when River first utters "hello sweetie", mentions crash of the Byzantium whilst flicking through the diary, is aware of Donna Noble, brandishes her own sonic screwdriver, recalls her Doctor having "seen whole armies turn and run away", and then tells the Doctor "the last time I saw you... you turned up with a new haircut and a suit. You took me to Darillium to see the Singing Towers. What a night that was. The Towers sang, and you cried."

The Vashta Nerada, initially, put the psychological frighteners on us, especially when the unfortunate Miss Evangelista ends up being dilacerated by the piranhas of the air. Moffat combines one of our most common fears - the dark - with sound effects of a foreboding swarm. But they lose their bloodlust lustre, somewhat, when they start using the skeletons of their victims to hunt down the remaining survivors like it's a game at a kids' Halloween party.

Catherine Tate continued to shine as the best companion since the show's return. Her helping behaviour towards Miss Evangelista's final moments is a standout albeit sombre moment.

The Library itself is a coruscant vista, although it's a bit odd that a mere 4022 people were on a planet-sized library when the Vashta Nerada attacked. Then again, we've now got holovids, direct to brain downloads, and fiction mist.