Pushing Back the Darkness

Remus Lupin was never bitten by a werewolf as a child. Instead, he was born a Metamorphmagus. At the end of his second year teaching at Hogwarts, already fraught with the events of the Triwizard tournament, Professor Dumbledore gives Lupin a special assignment: help a young, unorthodox Auror named Nymphadora Tonks after she is bitten by a werewolf.