I like it, i had already decided it was going to be based around an artifact. I somehow came up with a lot of the background for the campaign in the middle of it so i have had to been working on it from both ends and needing to create a start and a finish.
The Premise for it so far (a framework mind you)
The Planet Pavuvu are former imperial planet abandoned hundreds of years ago, for an (unnamed so far) Inquisitor Xenos to return to the planet in order to claim an ancient artifact with the help of the Dark Angels and Death Korps of Krieg. Upon arrival they discover the Tau in the process of colonising and terraforming the planet in the name of the greater good in order to support their growing population and need for natural resources. The Inquisitor discovers a chilling fact that the humans abandoned by the Emperor hundreds of years ago were accepted into the Tau Empire. The Artifact the Inquisitor is after is the same artifact that the Earth caste are using to power their terraforming efforts; upon learning that the Inquisitor plans to use this artifact (of eldar design) to power a weapon capable of obliterating entire solar systems the Eldar form an alliance with the Tau to make guarantee this never happens.
So there we have it, what do you think?