The Master is back! Assuming the alias of Professor Thascales at the Newton Research Unit at Cambridge University, he harbors his latest deadly plot to seize control of time itself. Can the Doctor and Jo thwart his terrible plan? What secrets does the mysterious trident-shaped crystal hold? Why is the ancient city of Atlantis central to the Master's plan? And what mythical terror lies at the heart of the Maze? With time literally against them, the odds might just be too great for the time travelers.