I have recently started a campaign with fresh players. First scenario was the initiation scenario "promises, promises" , and my players were reasonably horrible. They didn't finish that scenario yet, but I expect them to flop it, and the consequences will be for them to be kicked out of the covenant by their remaining sodales, and probably inherit a reputation within the tribunal that is bad enough that they want to move away.
One of them was born and raised in the normandy tribunal, and has story flaws tied to this region, so I wanted to bring them back here. The idea was that they receive an "offer" from the mask of a powerful covenant from that tribunal : they would receive political assistance to found a covenant close to a good source of vis with a relatively generous liege charter. In order to get this miracle-deal, they would first have to trick a raiding party from Montverde into attacking some bishop's convoy or something else that would provoke mundane outrage, by making it look like furnitures ordered by a covenant. The idea being to weaken Montverde's influence before the next tribunal (The mission looks a bit suicidal, but they will get hints and/or support from an older magus).
There is a point where I need help for this adventure : I have little knowledge of the potential of magic in ArM, and while I understand the rules of the order, I'm not sure I fully understand the tricks of the code. Would there be any investigation method from Montverde's or Guernicus quaesitores that would make this plan impossible ? What should the mundane reaction be to weaken Montverde's politic power without provoking a meltdown in the tribunal ?
Since mundane items are fair game for raiding in the Normandy Tribunal, I really don't see anything wrong with misdirection here.
This should be done with as little magic as possible. Misdirecting their agents, and then sweetening the pot. One thing that can be done, if there's something that the bishop, or whomever really wants in that shipment is to transfer a pawn of vis into it, that way Montverte would leave it alone, since it is inherently magical, and it would be a violation of the code to steal it, if they think they are stealing from other magi.
Quaesitors will likely investigate if it should come up, but the PCs might insulate themselves, if they preserve the most important item that whomever is receiving the shipment wants. And if Montverte fell for the deception and attacked a non-covenant caravan, well, they have the right under the Normandy Peripheral code to raid magi, but here they're getting perilously close to bringing ruin upon their sodales or something.
The mundane reaction is tough to gauge, because Montverte is already violating the code by controlling the baron who lives in the castle where their covenant is. They have a lot of temporal power at their disposal, so to speak.
Well, at least you chose the right Tribunal for your caper: the Normandy Tribunal is pretty much the only one where a covenant would consider attacking another's supply train 'business as usual'.
The mundane reaction: I think ideally the bishop would lodge an official complaint with the Order (there's an established method for doing that in all Tribunals according to Lords of Men, although it varies from Tribunal to Tribunal). The Order would then order Montverde to pay reparations (which is trivial enough), possibly a fine (a matter of politics), and the loss of face would translate into a loss of political power, which is what you are seeking. That means the bishop must have a mean of finding out who is responsible, or at least that magi are responsible so he can complain to the Order (if he doesn't, in the Normandy Tribunal there is no crime).
The investigation: magic cannot look into the past, so the players don't have to worry about that. Medieval investigation is in any case far more focused on witnesses than factual proof, so if they are careful to give the witnesses the wrong impressions their job will be done. Particularly if those witnesses can honestly say they believe the information (InMe magic can reveal that someone is telling the truth easily enough).
The one potential stumbling block: using magic leaves magical traces, those traces can be detected after the fact by InVi magic and they bear the sigil of the magus who cast them. (Great for proving Montverde's involvement if they try to deny it !) This is however relatively high level magic (at least level 30, easily more to have details or check a large scene). It's unlikely Montverde's investigators would have access to it, but the Guernicus often specialize in it. So if your players actually cast spells at the site of the ambush, or on the guards or goods being transported, that could trip them. There are ways around it however:
InVi magic doesn't reveal the actual spell, at most a rough idea of the effect.
after a few times the spell Duration passes, the traces become a lot harder to find.
The spell Shroud Magic can create a fake sigil, you might arrange for you players to gain access to it. Or for the players' support magus to cast it while they are casting any spell that might be traced. A decent Guernicus will still suspect the sigil is fake, but he'll have no way of discovering the real one.
The investigator must still first find the place/person/thing the spell was cast upon, and think to examine it. If a player uses magic to disguise himself and spread false information, he's safe enough: the Guernicus can check the people he talked to all he wants, he won't find any magic. And of course there's tons of magic traces on a magus, that proves nothing ! If the players don't use magic at the site of the fight, or on the actual goods being fought over or the guards escorting them, their magic will probably never be discovered.
It doesn't even matter if Montverde or the Guernicus suspect other magi had a hand in it. Montverde attacked the bishop's possessions, he complained, Montverde is guilty of breaking the Code, that part still works. There might be repercussions later if the players are revealed as the ones responsible.
The fact that a wizard's sigil is identifiable might be the reason PCs are desired to pull this one off. If this requires casting spells, the sponsoring covenant might want to have sigils that no one can identify. So sigils of magi from outside the tribunal. Preferably young ones, so that perhaps even a quaesitor from that distant covenant won't know their wizard sigil. Hence - the invite for these magi to come in and do this thing.
That's probably not enough to invite them in, but can serve as a "proof of principle" that these magi can be counted for as vassals to further their master's plots, while taking advantage of the fact that they have never-before-seen sigils.
Okay, thank you for your answers. I think I have a better idea of what they'll have to do now.
I think their helping hand will be a Tremere magus, that will add another layer of intrigue, and he may request other services later on, giving them another chance to get ressources (and maybe trouble with their parent covenant). Besides, I'm sure my Tytalus magus will be unhappy with that as he planned to take control of the politics in the covenant.