The Gemini Plan, sometimes called Project Gemini, was the invention of Rudolph Steiner. It was a scheme to knock Venus into Earth's orbit, thereby allowing humans to retrieve its neighbour's mineral wealth.
The scheme was to be effected by precisely-controlled nuclear explosions. According to the chart seen at right, an explosion delivered at orbital point "V1" would knock Venus into a "receding elliptical trajectory". At "V2", another explosion would bring Venus onto Earth's orbital path.
Murray Stevens, one of Steiner's assistants, saw the monstrosity of this plan and unsuccessfully attempted to sabotage it. He therefore had to go into hiding in underground caves in the Australian desert. There, he met up with the Third Doctor, also on the run from Steiner. The two quickly joined forces to stop what the Doctor called a plan that "could devastate not only the solar system but half the galaxy." With the help of some local Aborigines, the two scientists were able to thwart the plan. (TVA: Gemini Plan)