Human Nature is very much Martha’s story. It tells the tale
of her infatuation with the Doctor and shows the lengths she would go to in
order to ensure his safety, but most of all this episode shows the lengths the
Doctor is prepared to go to in order to preserve his own life and avoid his
body falling into the wrong hands.
The Family of Blood are a family of space scavengers who
desperately need the life force of a Time Lord in order to sustain their own
lives, they pursue the Doctor so relentlessly that he is forced to contain his
Time Lord self in a fob watch to push the Family off of his scent. The fact
that the Family can absorb the very essence of a life is pretty devilish as far
as villains go and their army of animated scarecrows was pretty creepy to
behold.
