How the young Vincent Crabbe meets and befriends Lady Beatrice de Gonville Musgrave in the Middle Ages in England, and how they discover their magical powers and embark on a series of adventures. They defeat a plot to overthrow King Adelbert, with the aid of the young Hessian twins, Euphemia and Ruprecht. They visit the twins in their castle, Schloss Kirschbaum, in Hesse, and rescue Clotilda Gunther from robbers who are after her valuable silverware. They present the twins' aunt with a spinet, since her hearing is no longer good enough for her to enjoy playing the clavichord. Vincent becomes enthralled with honeybees, and takes up bee-keeping as his lifetime enthusiasm.