In the third book in the Collegium Sorcerorum series, begun in Collegium Sorcerorum: Thaddeus of Beewicke, and continued in Collegium Sorcerorum: Thaddeus and the Master, four boys are taken to the Sorcerer's College to learn the most powerful forms of the practice of magic. None could know the immensity of the ancient Evil that some believe dwells there unseen. It is now been a year since Master Silvestrus of the Collegium Sorcerorum has gathered his four charges -- Thaddeus of Beewicke, Anders of Brightfield Manor, Rolland of Fountaindale and Zoarr of Mauretesia -- safely to the school of Sorcery to begin their magical education in the midst of the Dark Ages. There the Four discover that one of the Masters, Perditus -- in return for the promise of unlimited power -- is conspiring with the Daemon, Morag, to conquer and lay waste to the world through the employment of a horde of Morag's ravenous colleagues. Meantime, the four boys have formed loving relationships with their opposite members at the Ludia, the girls' school of Sorcery -- Marsia of Dorset Downs, Nannsi of Zorbas, Sonnia of Frantillia, and Molly-O'-the-Willows of Fountaindale. The couples' mutual love allows them to at last embrace the power of their Sorcery. Master Perditus, finally aware that his students know of his plans, seeks to exterminate them directly through the use of the Goblin Army, but in this he is challenged by the desperate defense of the Iron Company and Aelvae alliance. In a last united attempt, Perditus and Morag signal the Daemon Hordes to enter the world of the surface and overwhelm its defenders. It is Thaddeus, alone, who has a chance to stave off the invasion and defeat the insidious evil, but only -- if he dares -- by making the ultimate Sorcerous sacrifice. The apprentices' quest for knowledge and good is perilous and on the way they are confronted by a Ghost Lover, a Fire Horse, Dragons green and red, a Mad Hermit, a Giant Eagle, the deadly Red Tide, the Pilot Pontius, a Goblin Horde, a perfidious Porter and an expanding Stone Spell as they seek to unravel the mystery of the laughing presence in the Tower. The apprentices' adventures continue in the first book of the second trilogy of the College of Sorcery series -- Collegium Sorcerorum: Thaddeus and the Emperor.