All is not well at the Wenley Moor underground atomic research station: there are unaccountable losses of power-output; nervous breakdowns amongst the staff;
and then—a death!

UNIT is called in and the Brigadier is soon joined by DOCTOR WHO and Liz Shaw in a tense and exciting adventure with subterranean reptile men—SILURIANS— and a 40 ft. high Tyrannosaurus rex, the biggest, most savage mammal which ever trod the earth!

‘DOCTOR WHO, the children’s own programme which adults adore…’ Gerard Garrett, The Daily Sketch