Ch. 321The Missing Finger, Human Transfiguration
Snape confronted Sirius and Lupin, but Aaron persuaded him to hear their account of Peter Pettigrew's betrayal. After Snape transformed Ron's rat, the chapter ended with Pettigrew revealed as a man.
- Snape threatened to send Sirius and Lupin to Azkaban, while Aaron and Hermione urged him to hear them out.
- Sirius and Lupin explained that Peter Pettigrew was alive and hiding as Scabbers, and Aaron identified the missing toe as evidence.
- Sirius confessed that he had persuaded James and Lily to make Pettigrew their Secret-Keeper, then blamed himself for their deaths.
- Snape took Scabbers from Ron and used a spell to transform the rat into Peter Pettigrew.