A British schoolteacher, Nicholas, has left his girlfriend to take a job on a small island in Greece, replacing a man who committed suicide under mysterious circumstances. Nicholas meets Conchis, the magus (meaning magician), a wealthy recluse with a mysterious past that might include collaboration with the Nazis. The Magus's companion, Lily, is just as suspicious, lurking around in a ghostly state of paranoia. Slowly but surely, Nicholas is drawn into a bizarre game masterminded by this magician. The deeper into the game he is drawn, the more he senses danger... yet he cannot seem to untangle himself from the fascinating and compelling influence that the game is having on his mind.