England, the 1820s. As the Industrial Revolution gathers pace, the village of Killingworth is disturbed by crazed Luddite miners intent on smashing all machinery and engineers. But is there another cause of the situation?

The Master uses The Rani's mind-controlling parasites to keep a meeting of Earth's leading scientists from being cancelled, and helps her plant transformation land mines for The Doctor, as he continues to propose an alliance with her in ruling over Earth.