The Space Museum was the seventh story in the second season of Doctor Who. It was the first story to deal with the dimensions of time as well as space. While it presented many original science fiction elements, it still retained the elements of a typical story of the era.
The story’s cliff-hanger also presented fans with a preview of the Daleks‘ third appearance. Their return was awaited impatiently, a fact that was baited by the appearance of a Dalek shell in part one. This shell was the final appearance of the original Dalek design until The Magician’s Apprentice in 2015. The Daleks at the end of “The Final Phase” do not have the metal band of their predecessors.
The TARDIS jumps a time track and the travellers arrive on the planet Xeros. There they discover their own future selves displayed as exhibits in a museum established as a monument to the galactic conquests of the warlike Morok invaders who now rule the planet. When time shifts back to normal, they realise that they must do everything they can to avert this potential future.
Vicki helps the native Xerons obtain arms and revolt against the Moroks. The revolution succeeds and the travellers go on their way, confident that the future has been changed.
Read more at tardis.wikia.com.