Story Code 'DDD'
by Don Houghton
UNIT are providing security at Inferno, a top-secret experimental drilling project, and the Doctor arrives as an observer. Project Inferno is designed to penetrate the Earth's crust, releasing a previously untapped source of energy called Stahlman's Gas, named after its discoverer. Professor Stahlman dismisses the concerns of the project's executive director, Sir Keith Gold, and exceeds all the safety margins in order to speed up the process. However, the drill head starts to leak a strange green liquid, which transforms anyone that touches it into vicious primeval creatures with a craving for heat. The Doctor is accidentally transported into a parallel world by the partially repaired TARDIS control console, arriving in an England that is ruled by a military dictatorship. Here, the drilling project is at a more advanced stage, but the Doctor is prevented from stopping its progress by the fascist alter egos of his friends and colleagues. The crust is penetrated, and the resultant violent volcanic activity causes the planets destruction. The Doctor escapes back to our universe, where the drilling is still in progress, and tries to warn the project's staff of the impending disaster. At first he is disbelieved, but his words shown to be true when the power crazed Stahlman is transformed into one of the creatures. The Doctor, aided by consultant Greg Sutton, kills Stahlman with ice-cold blasts from fire extinguishers, and he manages to shut down the drilling with only seconds to spare.
Jon Pertwee (Doctor Who), Caroline John (Liz Shaw / Section Leader Elizabeth Shaw), Nicholas Courtney (Brigadier Lethbridge-Stewart), Olaf Pooley (Professor Stahlman / Director Stahlman), Christopher Benjamin (Sir Keith Gold), Derek Newark (Greg Sutton), Sheila Dunn (Petra Williams / Dr. Petra Williams), John Levene (Sergeant Benton / Platoon Under Leader Benton), David Simeon (Private Latimer), Derek Ware (Private Wyatt), Walter Randall (Harry Slocum), Ian Fairbairn (Bromley), Roy Scammell (RSF Sentry); Keith James (Patterson); Dave Carter, Pat Gorman , Walter Henry, Philip Ryan, Peter Thompson (Primords)
Produced by Barry Letts
Directed by Douglas Camfield and Barry Letts
Part 1 - 9th May, 1970 @ 5.15pm - 5.40pm
Part 2 - 16th May, 1970 @ 5.15pm - 5.40pm
Part 3 - 23rd May, 1970 @ 5.15pm - 5.40pm
Part 4 - 30th May, 1970 @ 5.15pm - 5.40pm
Part 5 - 6th June, 1970 @ 5.15pm - 5.40pm
Part 6 - 13th June, 1970 @ 5.25pm - 5.50pm
Part 7 - 20th June, 1970 @ 5.15pm - 5.40pm
*Featuring the Third Doctor, Liz, the Brigadier and UNIT
*Working titles: 'Project Inferno', 'Operation Mole-Bore' and 'The Mole-Hole Project'
*A scene was also recorded with the Doctor, Section Leader Elizabeth Shaw and the Brigade Leader listening to a radio report, which was voiced by Jon Pertwee; although producer Barry Letts decided to remove the scene from the transmitted version, it was included in the version sent to North America