The alien conspiracy's plan to infiltrate and replace key figures to facilitate their invasion.

Outside Ashbridge Cottage Hospital, the Brigadier and Munro examine a recovered fragment of the plastic meteorite—a lightweight, synthetic material that defies terrestrial explanation. The Brigadier orders heightened security around the …

General Scobie is led into a UNIT office where a life-sized dummy of himself stands, a chilling approximation of his physical form. Hibbert, visibly uneasy, attempts to downplay the dummy's …