The town of Salem's End faces the arrival of powerful demons—Abaddon, Belial, Azazel, Leviathan, and Asmodeus—as the seals are broken. Father Michael, Sarah, Tommy, Deputy Harris, and Elias struggle to find a way to stop the impending doom. Sarah discovers that the Sigillum Dei (God's Seal) could bind the demons but requires a great sacrifice. Amidst confrontations with the demons, Sarah performs the ritual, sacrificing herself to seal the breach and save the town.