This episode was such a relief. It was the best Doctor Who episode in six years, and boy did we need it. It is completely inventive, essentially a two-hander as we push the Fourteenth Doctor and Donna to the absolute limit and see what they are made of. The 'no-things' are absolutely terrifying, and the plot line is so intricate and clever. It brought back the rush that all the best Doctor Who episodes give. It's a tour de force by some of the world's most talented actors, and I loved every bit.