Athaliah the murderous mother is undone by Jehosheba the protective mother.

To be specific: Athaliah renounces her blood ties with her grandchildren and slaughters the royal seed (2 Kings 11). Jehosheba renounces her blood ties with her own mother, Athaliah, and saves the royal seed. Wicked family disloyalty is undone by righteous family disloyalty.