Believing the world needed a strong mind to unite it, such as himself, Vaughn had created an alliance between himself and the Cybermen and planned an invasion of Earth in exchange for power. Vaughn even allowed himself to be semi-converted into a Cyberman, however all the modifications were physical, and his mind remained untouched. Vaughn however intended to betray the Cybermen once they had invaded Earth. They worked together on the invasion plans for 5 years.
When he met the Doctor and Jamie McCrimmon, Vaughn was told by the Cyber Planner that one of the Doctor's pieces of circuitry came from his time travel machine. Vaughn planned to use this as insurance to escape with his security chief, Packer.
Before Vaughn could betray them, the Cybermen betrayed him and his plans began to crumble. He allied himself with the Doctor to defeat the Cybermen, out of hatred for them, but was killed by them in the process.
|“||You think I'm mad, that all I want is power for its own sake. No, I have to have power. The world is weak, vulnerable, a mess of uncoordinated and impossible ideals. It needs a strong man, a single mind. A leader!||„|