Avacyn answers a mother's desperate plea by finding her son, Maeli, lost in the forest. She brings him home safely, briefly fulfilling the promise of her protection. An intrusive buzzing then disrupts her thoughts. Watching the reunited family, she begins to perceive ordinary human anger and frailty as contamination. The contrast matters: a guardian who had just returned a child to safety is losing the ability to recognize the people she was made to defend.
Her violence reaches priests and villages. Bruna and Gisela support the proposed purge, but Sigarda rejects it: human beings can choose cruelty, yet they can also choose love and service. Their imperfection is not permission to destroy them.
The change is not a harmless dispute within an angelic hierarchy. Innistrad relies on its protectors to stand between people and predation. When those protectors identify their own charges as enemies, the institution that promised shelter becomes another source of terror.