Item advice sought.

I'm a fairly new GM as far as Ars M goes, and am wanting to put together a plot for a rather diversely experienced group of players. The plot seed I have in mind so far is something along the lines of 'red letters', either bringing good or bad to the person recieving them, or even sometimes simply a red herring. I'm wanting this to be a non-Hermetic bad guy basically, so does anyone have any suggestions along those lines?

My group is currently using 4th Edition, and I've looked at charms and banes as a way of doing it. don't know whether to make them specific effects, or simply have the letter act as some sort of 'beacon' to garner the attention of an entity of some variety, possibly in service of the original caster.

Any help would be appreciated!

Could you elaborate a bit more? You want some physical item to either give grief or prosperity to the owner/holder? Consider some Rego Vim effect binding a Faerie to it. Depending on what criteria you want to decide whether give good or bad effects, a Faerie could do either. Just make up a good story of who and what it is, what it wants in "life" and why it does what it does. Something not evil, but mischevius and (sometimes) rewarding.
Find or design an apporpriate Faerie, look at the ReVi guidelines to see what it tales to bind it (IMHO this is an inverse ward, you're not keeping him out, but in). And design the item to fit it. It doesn't do anything continuous, it just needs the constant effect to keep the creature inside. The creature itself uses his powers as fitting.

I'll try and explain myself better, somewhat hard as the plot seed hasn't fully formed in my mind and I'm fishing around for ideas more than anything!

Basically I want a series of these letters sent out by person currently undefined. Some are basically aids, some hinderences, some destructive and some red herrings. Hence leaving a bound fae to decide what to do doesn't really suit my purpose I'm afraid. Which is why I was looking at a charm or bane maker as a potential source. But yes, it would be a pyhsical item, delivered to a person which then causes an effect, not even necessarily immediately. Which is what's giving me the problem.

So, the author of the letters decidec upon good or bad intent. The letters pass this effect onto the reader, but the effect need not take place immediately. It sounds like some kind of conditional duration, where the spell lingers inactive until a certain thing happens, and then - Bang!
I'm not really sure how to do this off hand. Perhaps I can dig something up.

I just have to be awkward, I'm afraid.

Also willing to take suggestions on something along a similar theme. Never run ARs M before, so not wanting to make it too tricky!

Hrm, would an item work that once read releases a time delayed effect, thereby rending the piece of paper to be just that afterwards?

While not magical, the BBC series Psychoville started with the premise of an unknown man sending letters to a number of different people. All these people had very different lives, some apparently happy while others could clearly have gone better. But the letters were all the same: "I know what you did". The characters also received subsequent letters and (if memory serves) a key. Perhaps an enchanted letter has the capacity to become all of these things.

The Psychoville plot had all the characters related through a single event. That needn't be the case, but if there is a single source for the letters it sounds as though this is a unique planned act. So what would motivate someone to do this? And remember, a letter may form an Arcane Connection to its writer (though it mayexpire by the time it is received).

What happens if one of the letters fails to arrive? Or goes to the wrong person? How are they delivered? Is there a trail that could be followed back to the source?

I'd maybe look at a letter that changes its content over time, perhaps effects triggered by changes in the season or the month. Affecting magi with magic letters could be quite difficult, but giving them information (true or false) could influence their actions, which is perhaps more important.

I'd already considered the arcane connection angle, and indeed ways to avoid it as that would be far too simple a concept for my magi! And I'm basically working on the premise that it won't be a connection by the time it arrives, or rather that it becomes the property of the intended recipient as soon as they take delivery of it. I haven't seen the BBC series, might be worth a sneak look whilst the SO is out sometime. Nor had I considered the concept of one going to the wrong person, something certainly to add interest to the mixture!

I must confess we're not playing in a standard Ars M setting, more sort of steam-magica in Victorian times (we're Verditius heavy!), so there is a little more modernity at play here than a standard setting.

Would it be possible for an effect to be released, and then to automatically trigger when a set of conditions were met? Ie if the letter foretold death by say.. runaway carriage, could an effect to that intent be triggered whilst out and about on a street for example?

If the letters are sealed, which was not always the case, but certainly common for private documents, then you could have a spell trigger 'breaking the seal'. I honestly cannot remember how it worked in 4th, but in 5th you could make charged items for each of these. I cant remember if 4th was only potions that worked this way. If they are low enough level spells you can even get apprentices to make some, especially with a lab text.

items type one: the red wax.
Trigger, breaking the wax (seal)
Effect - ReCo that makes you go blind for a day

item tpe two: the yellow wax
Trigger, breaking the wax (seal)
Effect - ReMe possitive effect such as aura of rightful authority

type 3: the green wax
effect eyes of the cat spell, duration sun
I think yu get the idea...

You would could keep adding types over the seasons until you had quite a vast collection, and as charged items you can make large batches and swap the types about from your growing stores. In a year of preparation you could make 4 to start with and if some of thoese effects are a bit random, like warping, you have a fair range to get going.

By making the wax as the charged item and the trigger breaking it (when set) you can use them much more flexibly than enchanting each individual letter. Using charged items also circumvents the vis limitations of mediums like papar and small wax candles.

Alternatively... have the trigger effect cause warping... enough warping to force an outcome / twilight check.

All that said, I cant remember for sure if you can actually add triggers to charged items... doh!

You can do this, but the device generally has to have an intelego spell to KNOW the trigger condition has been met. The intellego spell needs to know when to trigger too. This works best with traps etc, it requires a bit more imagination with less obvious things.

e.g. trigger - opening the door triggers an InVi to detect magical creatures. trigger 2 (if magical creatures are detected) cast ball of abyssal flame.

Hrm, I was actually thinking along the lines of a non-Hermetic. Messy to meddle with members of the Order when you're on the inside. A certain house tends to get its knickers in a twist.

How about if a spirit were released? It could have been given a set of instructions to follow once free?

You could do that... ofcourse the manner in which you had 'bound the spirit' and forced it to follow instructions is likely to cause problems. They tend not to like that sort of thing. Then there is the business of finding so many spirits if this is a series of letters to a number of people. That is quite an effort and you are going to attract quite a reputation as a spirit taker quite quickly form wherever you are capturing them.

Perhaps take a more direct approch to the actual boons / curses by casting them directly on the targets without their knowledge. Linking the letters thematically to the effect you plan to do. A lot of 'curses' can be accomplished by acts of violence by skilled agents.

Finally, you can get demons to do all sorts of things for you... all you need to offer is body & soul... and not even all at once. They would love this litte charade as soemthing that would probably lead a number of people towards sinful activity.