What made this episode great was the creepiness factor. Now be aware. I don't watch scary movies and I definitely don't read horror books. (I never even opened the one Stephen King book I bought). Doctor Who is about all the scariness that I can handle but I love it! This episode plays on your fear of the unknown which is sometimes worse than having a real monster. Even though people bring up the weeping angels as one of the scariest episode I find the vastra narada in "Silence in the Library" or the monster in "Midnight" more frightening because you cannot actually see the creature. This episode plays on the fact that we might never really be alone. The monsters are hiding everywhere, we just can't see them.
This episode also shows us, once again, that Clara is a pretty awesome person. I had an epiphany the other day and decided Clara is great in these episodes because she has faults. This new Doctor brings out her faults in the best way possible. With Matt Smith she was the pretty plot device who was fated to save the Doctor regularly. Now her relationship with Capaldi has changed so she is no longer just a pretty face but a spunky woman.
Now I won't say too much more because I don't want to spoil anything but I will say that this episode reveals some interesting things about the Doctor and Clara. We get one step closer to learning about this Doctor and his past all the while doing the same timey wimey thing as always.
What did you think about this episode?