The Black Sepulchre is the first adventure of the Apostasy Gambit trilogy (the other two being Church of the Damned and The Chaos Commandment) by Fantasy Flight Games. The whole trilogy spans many months and many ranks, as the acolytes develop from fresh recruits to determining fate of the sector... it's epic beyond words.
I recently ran this whole campaign to a live group (taking them from the second rank to the edge of ascension over a couple of months of active gaming). It went really well but I couldn't help but feel "If I ever ran this section again, I'd want to put a bit more emphasis on that part..." and that kind of stuff. I've also been thinking that I want to get back to PbP GMing, so... here we are.
The Apostasy Gambit consists of three books, each of which is divided into three or four chapters:
The Black Sepulchre starts with a bang, as the acolytes participate in a raid on a corrupt aristocrat's mansion. After that there is some good old fashioned investigation and finally exploring a large, abandoned complex. I wouldn't call it hack'n'slash but it's certainly action-oriented and relatively linear.
The Church of the Damned is full of intrigue and tactics as acolytes have to go undercover to investigate very prestigious organizations and track down very infamous criminal.
The Chaos Commandment is a demon hunt in a sector torn by civil war. There is everything from leading open assaults to infiltration, with a quite a nice bit of horror mixed into everything.
As mentioned earlier, I will make some minor modifications based on my experience on already having ran this campaign once... but in general, I will go more or less by the book. If someone is interested, I'd love to have a backup-GM/co-GM to ensure that everything goes smooth and reliable (=me having to be away a few days wouldn't halt the game, players would have more security against the infamous PbP GM burnout, etc.). This could be one of the players or just a spectator.