Denzil's Dilemma

Safe in his medieval village, Denzil is sure the old woman is mistaken, and theta the warning is not for his master, the great wizard Valvasor. The only way Denzil can reach Valvasor in time to warn him, is to use one of Valvasor’s magic spells – a spell which, in the hands of the apprentice, goes horribly wrong…Denzil is carried seven centuries into the future, and appears in the MacAllister’s back garden. How will he convince them that he really is a medieval wizard? And how will he get back to his own time, to warn Valvasor about the dragon?