Ian Elliott

When scientists in the Antarctic uncover a mysterious seed pod, the Doctor is called in to investigate. He soon realises it is extraterrestrial and extremely dangerous. At the same time, however, ruthless millionaire plant-lover Harrison Chase has learned of the find and decides he must have the pod for his collection of rare and beautiful flora. Meanwhile the pod itself harbours intelligent life with sinister plans of its own...

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.

In the western town of Coal Ridge, a deputy keeps his love a secret until the outlaw who stole his heart is taken hostage.