Ten years after the Daleks' 2164 invasion. On the planet Tara, a great plague wipes out nine-tenths of the world's population. Once the plague runs its course, it is decided to replace the dead with a number of androids. This world is home to the Great Vampire, the last of a race of Vampire destroyed by the Time Lords thousands of years previously. The Great Vampire takes control of the Hydrax crew, who become rulers over the village of peasants the Vampire feeds off of.
Date is conjecture.
The Hydrax is an exploration vessel, so I am placing these events during this century, one of Earth's earlier exploratory periods. On the planet Vulcan, Deputy Governor Quinn secretly contacts Earth, asking for an Examiner to come the Vulcan and help deal with the rebels. Around the same time, a space capsule containing three Daleks in found buried in a swamp by colonists on the planet Vulcan. On the Earth colony Vulcan, the 2nd Doctor, Polly and Ben discover a group of Daleks pretending to serve the colonists. The Doctor manages to overload the Daleks' power systems, but not before most of the colonists are killed.