I am creating an adventure based on a navigator house and I want ideas/help. The basic story is that mysterious happenings and deaths have been happening in a very affluent section of a noble/pleasure world. It turns out that two navigator houses are having issues with each other. One house is has raided the dungeon of another, where failed genetic experiments, older family members who are no longer able to work or be in public from prolonged exposure to the warp, and the "still born" family members/monsters. The raiders have lost several of their captures and want them back. While the original house can not let these embarrassments be found out about or their trade secrets get out want the escaped and captured dead. And a third house wants to expose them so they loose face (and contracts).

So basically the characters are thrown into a three way war. With two houses wanting it kept quite and a third trying to find out about it and expose it. The players can stay neutral or get on a houses side, or try to work with the other nobles that want the deaths to stop.

So, I'm not sure if you're asking anything in particular here.

I'd exclude the third house, and just keep it down to a war between navigator houses.

The Ordo Famulous of the Adeptus Sororitas would likely want to be informed because that kind of networks is very important to keep together for the sake of the imperium.

You'll certainly get some Rogue Trader interest (or at least assets involved in the war so far) because of the navigator houses pulling ties.

And as always Navigator's fall under the Ordo Hereticus' purview so lots of fire. Desired by the players or not.

The biggest thing will be figuring out the planet to hold it on and the houses (called clans in DH2) to involve.

Terminus Prime seems a likely place this might happen based on the description.

A couple of clans to look into involving. Ursa and Auriga Navigator Clans respectively are the ones I found on a quick scan through.

There are plenty of Rogue Trader dynasties mentioned in the books to draw from as well should you want to involve them.

I thought the third clan would be brought in later as a further complication, if the players screwed up and let the secret out (which they most likely would). But the idea of a Rogue Trader might be just as good, if I can figure a convincing reason why one would be involved. Maybe the RT wants them to start a private RT controlled clan.

I put these things out to bounce ideas off people and get feedback. Also, people have written up pages of story and other information for these adventures by me just putting out the idea. I didn't think of Terminus Prime, but now I will look into it. Plus I want to encourage adventures in DH that don't revolve around deamons, as most DH stories seem to do.

You already have two navigator houses, which will be somewhat similar in flavor, I feel like adding another would dilute the uniqueness of the situation really. Navigators are a small clannish bunch their numbers are drastically few in nature. They'd likely keep to themselves at all cost.

Why wouldn't a Rogue Trader dynasty get involved in a navigator war. If their family's clan loses then they are out a bunch of navigators and the family falls into ruin.

I feel like the relationship between navigators and traders is a bit different. Most families have a clan they solely associate with already, but the clan has a lot of negotiating power because they're the only ones that can do what they can. Unless the dynasty is particularly business savy or ruthless the Clan can lend out navigators to whom they please.

If you're dealing with people that have warp organs in the middle of their skull and routinely look people to death, you're gonna find a daemon or two.

I'd second dropping the third Navigator House. I'd recommend adding the Rogue Trader though! Just think about a canny and unscrupulous Rogue Trader who learns about the Navigator mutants and the leverage potential, might just want to use that to extort and blackmail the 1st Navigator House into signing very preferentially oathsworn contracts with his dynasty (perhaps his dynasty has no iron-clad alliance, his navigator house went defunct, or some other reason). Either way, this is a chance to tuck yet another asset under the trader's belt. Add's flair.

OK so the basic plot is the 2 nav clans and a RT to come in later. I'm thinking that the escaped, while initially thought to be one killer/monster by the party are actually several. Each causing trouble in its own way. One who causes people to see the warp around them. One who is acting like a serial killer who can shift reality so he can't be seen, killing those he sees as feeding the warp bad vibes, Lust, Anger, Decay. A third who is basically a third eye warp blast canon. This should give the characters plenty of things to chase round until they get involved in the conflict between clans. I'm thinking one of the captured has charted a new warp passage but went mad. I'm thinking that the houses will either try and kill the investigators to keep things quite or befriend them to use against the other clan and them kill them.

My one observation - raiding the dungeon (to essentially gather evidence of "embarrasing mutant" status) is an interesting choice; after all, the raiding house probably has its own bag of unpleasantnesses downstairs too, and the last thing it'd want is people going looking.

Plus, how did they manage it? Not impossible (it just takes resources, brains and planning) but the raided house will want to know.

Second, what is the raided house going to do as revenge? (there will be some; actively shooting your way in and kidnapping members of the bloodline isn't the same as poisoning servants, bankrupting trade deals or similar. It's going too far. Something must be done .)

The acolytes getting involved to hunt down the scary three-eyed serial-killing flesh blob (or whatever) is an interesting 'in' to a campaign, especially since their inquisitor (or other suitably senior minion thereof) will probably take one look at the corpse and go "that's a Navigator. Bugger.", throwing them straight into the politics side of it.

If you really want to lampshade something scary, you could always scale matters up and have it be one of the really impressive navigator houses - because if you want to scare the players, there's always the option of House Belisarius, who have some especially dangerous individuals to whom this sort of task (tracking people, dealing with nefarious violence) might be entrusted - and if there are already rumours of monsters in the night, that won't help either.

The idea that one of the escaped has vital (to the Nobilite) secrets in his brain, so can' (as far as the Nobilite are concerned) just be killed is a nice idea, too.