This is one of the best from the latter Fourth Doctor era. Meglos captures the essence of the mathematic-scientific theme so common to Tom Baker's last season and Peter Davison's first. The culture of Tigella is divided between scientists and spiritualists. Neither knows true nature of the Dodecahedron, the powerful 20-sided orb that powers their civilization. Meglos is a super-intelligent plant who can alter his shape at will. With a motley group of space pirates he goes in search of the Dodecahedron. Those who liked Leisure Hive, Warrior's Gate, Logopolis, and Castrovalva will like Meglos.