Plans for his replacement, (Ben, in following story, The War Machines) got underway and it was decided that the female companion, Dodo (Jackie Lane) was going to be written out in the next story as well.
The Date: Far into the Future
The Place: An Unnamed Planet
The Doctor and his friends, Steven and Dodo, land on a planet which is filled by two faces of people. There was fur-covered savages and a highly-advanced race living in a high-tech city.
The leader of the advanced race claims that they can survive by draining the "life force" from the savages for their own ends and when the Doctor finds this out - he is outraged so the leader of the "advanced" race decides on a terrible decision ..... the Doctor has great knowledge and the Doctor and his companions will join the savages for the "Savages" in the city to be drain their knowledge and life force.......