A smart script which races along, a terrific performance by Peter Capaldi which marks this new Doctor as being quite different to his last few predecessors and a return to a version of Clara Oswald is smart, funny and worthy of being the Doctor’s companion. Possibly, I think, the best episode of new “Doctor Who” that we’ve had in a while. Certainly, it feels like it would fit into Moffat’s first, exciting season with ease, rather than the bloated mess that were the subsequent Matt Smith outings.