A new form of radar picks up sentient life – except on a nearby hilltop crowned with a circle of stones. Martin Jarvis and Patricia Gallimore star in Stewart Farrar’s sci-fi serial

Researchers develop a system than can detect sentient life. But some unknown force has other ideas.

‘Just think what you have here. Biodar – the first radar in the world, so far as we know. that can pick up sentient life and locate it exactly …’

Working on Biodar, Peter Brent and Margaret Govan are puzzled because Maiden Tor, a nearby hilltop crowned with a circle of stones – The Twelve Maidens – comes across as a complete blank on their screens.