The Dominators, Episode Three

The TARDIS materialises on Dulkis, a world where war has been outlawed. Several years ago, atomic tests were conducted on the Island of Death, but now a survey team from the local university discovers that all of the radioactive fallout has vanished. The Doctor and his friends aren't the only visitors to Dulkis; two Dominators and their robot servants, the Quarks, have landed on the island, and their ship has sucked up all of the radiation into its engines. When the Dominators encounter the members of the survey team, they take them captive and work them to exhaustion, clearing space to drill into the bedrock of the island while testing the Dulcians' suitability as slaves. The Doctor must convince the complacent senate of Dulkis that their world faces a real threat - before the Dominators destroy the entire planet simply to fuel their space fleet.