Years ago, brave Master Gregory (Jeff Bridges) succeeded in capturing evil enchantress Mother Malkin (Julianne Moore), and locking her away to rot in prison. Now Mother Malkin has escaped, and she's hungry for revenge. As her followers gather power, the dreaded witch reveals her infernal intentions to the noble knight who once imprisoned her, and who now has until the next full moon to train Tom Ward (Ben Barnes), the seventh son of a seventh son, to defend humanity against a threat whose evil knows no bounds..