Astrophysicist Adam Brake and his son Matthew arrive in an ancient English village to study the magnetic property of the prehistoric stones which enclose it. They discover that the stone circle is aligned to a Black Hole, and that the villagers are in thrall to Hendrick, a sinister magus. They also discover that they are caught in a time trap, a present in which the future can only repeat the past. Adam and Matthew then have to use all their ingenuity and courage to try to re-enter their own time and place. The television series is constantly voted among the scariest TV programmmes by SX magazine.