The bundle of energy that occurred in 42, and to some extent towards the end of the Lazarus Experiment is carried forward into Human Nature, but to much better effect.
This is a total game changer of an episode, Paul Cornell's script is outstanding, having read and loved his original novel it was so good to see it adapted.
In brief the Doctor is humanised and has becomes a Teacher at a Public School in 1913. Elements of the Doctor's true life seep through and he remembers his Timelord existence. His Timelord existence is hidden from pursuers the Family of Blood. Whilst there his human persona falls for Nurse Joan Redfern, whilst a lovesick Martha looks on.
This is without doubt one of the richest scripts/episodes to this day, so many wonderful elements, his book 'Journal of impossible things' is stunningly put together. The concept of the Chamaeleon arch is such a hugely imaginative one. The scarecrows are visually wonderful, and so terrifying as they are a real creation.
The School is fantastically realised, and Pip Torrens make a great headmaster.
Jessica Hynes is an absolute revelation, she can't be faulted one bit, and each member of the family is fantastically well realised.
Annoyingly the usual harping on about Rose is still with us, this should have been knocked on the head a while back.
Everything about this feels like a golden jigsaw, it all fits together sublimely. It really is so good. A perfect 10/10