Patrick Troughton plays the second Doctor in this four–episode adventure from 1967, set on Earth's moon and featuring a return appearance by the emotionless Cybermen. The year is 2070, and Earth's weather is controlled by a device called the Gravitron, based on the Moon and manned by an international team of experts. The TARDIS arrives to find the base in the grip of a plague epidemic which is drastically reducing the personnel. Before long an even...