Two girls bond over knights, castles, toys, and real treasure in this series opener inspired by a video game.Nine-year-old Demelza Penrose and her pet goose, Captain Honkers, live in a little camper on a caravan site owned by her father on Penfurzy Island in Cornwall, England. Demelza's life is upended when a mysterious girl called Nessa breaks in during a storm. When Demelza finds out that her father needs to sell the camper park due to declining revenues, she and Nessa spring into action to defend the property. Their discovery of Demelza's deceased mother's notebook containing clues to the legend of the Penfurzy knights and their lost treasure propels them on a series of hair-raising adventures. Fixing up a couple of old bikes to serve as steeds, the girls embark on a lengthy quest, which takes them to a junkyard in search of the Staff of Truth, up a high tor, and into a sunken castle where they engage in battle with sinister knights and discover a roomful of treasure. A satisfying plot twist ensures a happy ending for Demelza and her father and cements the girls' friendship. This is a lighthearted, swashbuckling tale in which physical bravery as well as smarts and honesty are rewarded. Expressive cartoon-style black-and-white illustrations dot the pages. Nessa is of Asian Indian descent; Demelza is cued as White.Future quests for these adventuresome girls are assured-and will be most welcome. (map) (Adventure. 8-10)