I've come across Elia's Peattie, The Shape of Fear but I can't figure out the meaning of the following sentence. Is it an idiom or phrase?
"Purity seemed to dog his heels, no matter how violently he attempted to escape from her. "
Some dogs (sheep herders) nip at the heels of the sheep, to direct them.
So the implication is not merely of following, but of changing the behavior of the one followed.