Deep in the Forbidden Forest, Remus confronts Castor, the werewolf sent by Greyback to recruit him. Their tense negotiation is interrupted by Livia, who sets the forest ablaze to force Remus to join them. In a desperate moment, Remus successfully casts a powerful Patronus that drives the werewolves away, thinking of Sirius and their love to fuel the magic. He escapes back to his friends and reports to Dumbledore, who praises his bravery while Remus grapples with the moral complexity of his actions.