The plot follows the quest of Avalon's young princess Gwenevere and her friends Fallon and Tamara to secure the scattered enchanted jewels, stop the evil Lady Kale from taking over the kingdom, restore harmony in magic and bring their mentor Merlin home. In the second season, the Jewel Riders receive more powers and new costumes; a new villain, Morgana, is also introduced in addition to the returning Kale, as is a new set of magical jewels to find. In the original version of the show, the title character has her name similar with Arthur's wife, Guinevere; other Arthurian characters in the show include Merlin and Lady of the Lake.