by Don Houghton
starring Jon Pertwee
with Caroline John and Nicholas Courtney
Dr Who ...starts a new adventure today
An apparently motiveless murder brings the Brigadier to the 'Inferno' - a terrifying project to drill through the Earth's crust. The Doctor and Liz are already there as observers - but the Doctor has plans for a dangerous experiment of his own.
(Dr Who's Who's Who: pages 50-53)