It is the third year since the strange castle, known to the residents of Calder Cove as Merlin's School for Ordinary Children, appeared in the seaside town. They are still viewing it with trepidation, more so this year as things that had been accepted - though odd - suddenly become dark and dire when a teacher is killed. Students are now more than ever reluctant to enter the confines of the building, but their choices are removed by an enchantment that draws the selected few in.

Will they find out who the murderer is before it's too late? Or will the murderer find them first?