Assuming you're referring to the season finale of Doctor Who in which the Master conquered the world, "The Sound of Drums"/"Last of the Time Lords", he reconfigured the Doctor's TARDIS into a paradox machine that connected present-day earth and the future so the Toclafane could come back and invade earth, interfering in their own past. (How? Perhaps he reversed the polarity of the neutron flow...)

His purpose was to conquer earth and use its resources to create a fleet of starships which he could use to conquer the universe. The problem with this plan is that it had one particular point of failure: if the paradox engine was disabled, it would completely undo the time-loop he had created, snapping everything back to the way it had been before the machine was turned on. This, of course, happened.
Source(s):
http://tardis.wikia.com/wiki/The_Master
http://en.wikipedia.org/wiki/Master_(Doctor_Who)

Asker's Rating:

Permalink | Report