UNIT is providing security cover at an experimental drilling project at Eastchester, designed to penetrate the Earth's crust and release a previously untapped source of energy. Soon, however, the drill head starts to leak an oily green liquid that transforms those who touch it into vicious primeval creatures with a craving for heat. The Doctor is accidentally transported "sideways in time" by the partially repaired TARDIS control console into a parallel universe where the drilling project is at a more advanced stage. Thwarted by his friends' ruthless alter egos, he works to save both universes.
Don Houghton | Writer |
Douglas Camfield | Director |
Christine Rawlins | Costume Designer |
Fred Hamilton | Camera Operator |
Martyn Day | Editor |
Marion Richards | Makeup Artist |
Terrance Dicks | Script Editor |
Brian Hodgson | Sound Effects |
Delia Derbyshire | Music Score Producer |
Ron Grainer | Music Arranger |