Remus returns from his first year teaching at Hogwarts, struggling with memories the castle stirred up and reconnecting with McGonagall, Flitwick, and Madam Pomfrey. He teaches Harry's classes and deals with Snape's hostility while taking Wolfsbane Potion monthly. During the events at the Shrieking Shack, Remus discovers the truth through legilimency—Peter Pettigrew was the real traitor and Sirius is innocent, but in the chaos of the full moon transformation both Peter and Sirius escape. Remus returns home to Grant and explains everything, realizing he should have trusted Sirius all along.