Dark Heresy Campaign Idea

i was thinking of this campaign for Dark Heresy and i wanted to get some feedback before i put too much effort into it

After the mysterious disapperance of a Planetary Governor of the Hive World Cin, the acolytes were charged with his murder and sent to a penal colony to rot.

The inquisitor gets a hold of your party and tells them that there is a suspected chaos cult trying to gain political power after the governors disapperance.

The following week, a strange man bearing a symbol of Cin comes and gets you from jail, claiming to be working for the Inquisitor. He allows you to pick from a list of predetermined inmates to join you on your quest (yeah NPCs!)

The inmate will have a democollar and a chem-inhaler
You and the new party member (aptly named Inmate 001) are transported back to the Hiveworld

yadda yadda
you infiltrate the cult, but when you try to find the leader, it turns out to be the strange man from the jail who busted you out, and the inmate then turns on you

party tries to escape but soon learn that rebellions are erupting all over the world and the ALPAH LEGION rears their ugly heads

so i still have a lot of fleshing out and general work to do, but this is the basis
and i don't want to be the railroading dm or whatever, so i was going to mix in some side quests and useless, but interesting, xeno-tech

opinions?
comments?
rants?
all are welcome

I see one glaring gap.

If the man who came to get you was indeed the cult leader (and the other inmate was in his employ) why bother to release you at all? Why not just let you rot in jail rather than give you the chance to take him down.

I would also be wary of using Space Marines (more than one or two anyway) as antagonists in a dark heresy game, the game is deadly enough! If the Alpha Legion are indeed at work on Cin... it would be best to have it be just a handful (as is common with current Alpha Legion tactics anyway, inspiring a small enclave of humans to do their work.)

Just a few thoughts.

ok how about this

the cult leader wanted to flush out the inquisitor, and he used your party to get to him, and by killing the Inquisitor, the cult leader could take over unmolested

and when you figure out he is the cult leader, the Inquisitor BUSTS INTO THE SCENE DRAMATICALLY!

and maybe i can have 1 Alpha Legionaire, i haven't looked at the stats because my friend hasn't lent me the book yet