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.
Although Bridgette and Duncan were able to escape the Otherworld, their adventure is only just beginning! As the chaos of Arthur's return reaches London, an artifact at the British Museum is stolen. But is it Arthur who's interested in the relic... or someone, or something, new?