The time since Matt Lumen's eventful winter vacation has passed quietly and he has adjusted well to life with the Guardians. However his peace comes to an abrupt halt when a strange man comes to him in his dreams, warning of a threat surrounding the diary of one of the most powerful warlocks ever to have walked the earth. Matt and his friends soon find themselves racing against the Order of Shadows to find what could be the Holy Grail of magical knowledge. In a race against time, the Guardians come face to face with Zedric's newest and most fearsome agent: his own apprentice.