A Purer Evil is, as one reader put it, "a werewolf tale for grown-ups".
Arthur Lehmann is the new pastor of a quiet Episcopal congregation in rural Ohio. He has come there to grieve and reconstruct his life after the tragic death of his pregnant wife in a car accident. He wants nothing but peace, quiet, and an undemanding routine to dull his pain. His only companion is a dog.
Then one night, while walking his dog, he is attacked by a strange animal, and his peace is destroyed forever. His passions and zest for life return, but there is something horribly wrong. He is slowly changing, into what he does not know. Then, under the full moon, the change is complete. He is consumed by the primal cravings of a beast: he hungers, he craves, he lusts.
Lehmann has become a monster, what people call a werewolf, a slave to primal urges that threaten to take him over, to drag him down into a squalid world of subhuman creatures where a quick death is his most likely fate. He must fight for his mortal existence and for his eternal soul or he will lose them both.