On the morning of March 16, 1978, the US owned, Liberian registered supertanker, the Amoco Cadiz, went aground off the coast of Brittany. Over the following days and weeks its entire 68 million gallons of oil drained into the sea. A NOVA production team began filmming at the scene shortly after the disaster, the biggest oil spill in history, and recorded clean-up efforts, effects of the spill on the crucial tourism and fishing industries, and the attempts of US and French marine biologists to trace the passage of the oil through the environment.

The massive Kroll is awake and killing anyone in its path. And the swampies are determined to appease it - by sacrificing the Doctor and Romana.