Conn should have dropped dead the day he picked Nevery's pocket and touched the wizard's locus magicalicus, a stone used to focus magic and work spells. But for some reason he did not. Nevery finds that interesting, and he takes Conn as his apprentice on the provision that the boy find a locus stone of his own. But Conn has little time to search for his stone between wizard lessons and helping Nevery discover who or what is stealing the city of Wellmet's magic.

    It’s not enough that his mother has sent him away from home to learn magic. It’s not enough that everyone at his new school calls him Thornmallow because he’s “prickly on the outside, squishy within.” It’s not enough that the only talent he shows at Wizard’s Hall is an ability to make messes of even the simplest spells. Now, when Wizard’s Hall is threatened by a cruel sorcerer’s fearsome beast, it is up to Henry--er, Thornmallow--to figure out how to save not only his new friends but also the entire school for wizards.

    It's snowing and the Seven are dressed in disguise, following a lead to a spooky old house - and a mystery.

    He takes them into the caves of Fundindelve, where he watches over the enchanted sleep of one hundred and forty knights. But the heart of the magic that binds them - Firefrost, also known as the Weirdstone of Brisingamen - has been lost. The Wizard has been searching for the stone for more than 100 years, but the forces of evil are closing in, determined to possess and destroy its special power. Colin and Susan realise at last that they are the key to the Weirdstone's return. But how can two children defeat the Morrigan and her deadly brood?