When a group of Nationalists use an ancient artifact to bring a villain from Arthurian myth back from the dead to gain power, ex-monster hunter Bridgette McGuire escapes her retirement home and pulls her unsuspecting grandson Duncan, a museum curator, into a world of magic and mysticism to defeat a legendary threat.
With the fate of the world in the balance, Duncan must finally accept his role in the larger story. But has Gran trained him well enough to defeat the undead King of the Britons by himself?