D&D 5E Tracking undesirables

[ammulder]

Let's imagine you're the King and you're hosting a delegation from the next-door country full of thieves or similar sketchy characters. You have to treat them well, because diplomacy, but all the same you want to sort of keep an eye on them while they're in the city. Don't want them recruiting spies, stealing the crown jewels, releasing political prisoners, making contacts with the local thieves' guild, slipping poison into the royal kitchens, or whatever else your paranoid imagination might come up with. You have the royal mages at your disposal, though whether magic is the best approach is part of the question.

So: how do you keep these folks from misbehaving, or at least make sure you're aware of anything untoward going on? Is there some combination of spells/items? Old fashioned boots-on-the-ground (place your own spies, or assign skilled adventurers to keep tabs)? Keep them so busy with scheduled events that there's no time for anything else? Other ideas?

 

[Horwath]

How do you battle spies and thieves?

Hire your own spies and thieves to watch then and set up your defenses.

Better yet, pay some of the guests that they spy for you now.

Not many wars have been won without winning the intelligence/counter-intelligence "shadow war" first.

getting adventurers would be good plot hook as you mentioned.

throwing around arcane lock as candy would also do the trick.

post double shifts for guards around palace/town.

Make sure that the event is after some state/religious holiday that you have been generous to the common folk.
People get their patriotism high for a while when they have been "greased" by the ruling class. Might get more difficult for foreign spies to "grease" them instead.

Make the law that all weapons and spell components are illegal except for your people with high enough "clearance level".

 

[ammulder]

Arcane Lock is a start, for the most predictable targets/routes. The down side is that Knock is reasonably accessible and doesn't alert you in any way when it's been used on the Arcane Lock. Also, outside of really critical places, you might need to use the password option because it would be too unwieldy and error-prone to try to list who gets access. And then you have to worry that a spy could buy the password.

Locate Creature might be good, though in a decent-sized city it's probably only a starting point.

I'm not considering changing the law, though I had to smile at the thought.

The problem with doubling the guards is that it's expensive, and mostly doesn't cover the right places. Almost by definition, the thieves/spies are going to be skulking around the places where the guards aren't.

Though, I'll have to think about the political angle. Could you tell the delegation "since our lands aren't the best of friends, I'm assigning you guards for your own protection"? Might be too transparent.

It seems like you'd want to rely a lot on counterspies, but I can't help thinking there's some magic option I'm missing.

 

[RulesJD]

Magic. The answer you're looking for is Magic.

Alarm spells everywhere. For days.

Arcane Lock because Knock lets out an audible noise (300ft) when cast.

Dream spell would let you know what they're up to.

Detect Thoughts on all guest at the basic level to see what they're up to (feelings of nervous fear/betrayal on their mind).

Illusion Spells. Cast illusions of your valuable items with Alarm spells and Non-detection spells around them.



Really you're only limited by the amount of magic you have access to and your imagination. Take all of the blasty spells off of the Wizard spell list so you don't get distracted and start seeing what's available.

 

[Ed Laprade]

Assign each member of the delegation a 'liaison' that they can't go anywhere without. And a bodyguard. Refusing would be a major insult. (Or so they would be told.) Then add a bit of magical protection to the most sensitive areas and Hey Presto, you're as secure as you're going to get.

 

[Lanliss]

Concoct a massive number of massively deadly traps. Put them everywhere, and tell the spies this. Don't say the traps are for them, say you had a break in or something, and upgraded security.

Warn them that these traps will instantly kill just about anyone that does not know the proper way through. They must guided through these trap areas, and the paths through are more difficult and more closely guarded the more important an area is.

Bonus points for screaming "STOP" in the main Foyer of the palace, and walking in a careful pattern across it (even if there is no trap) and reaching behind a curtain to "disarm" the trap.

 

[Satyrn]

Kill the spies. Send dopplegangers home in their place.

 

[Mad_Jack]

Assign each member of the delegation a 'liaison' that they can't go anywhere without. And a bodyguard. Refusing would be a major insult. (Or so they would be told.) Then add a bit of magical protection to the most sensitive areas and Hey Presto, you're as secure as you're going to get.

This... Give each member of the group an entire entourage - liaisons, servants, bodyguards, etc... And then have a social schedule that doesn't give them much time to get up to anything.
Also, it wouldn't be the main members of the delegation getting up to anything, unless they're spellcasters or assassins - they'll work through servants, secretaries, minions, intermediaries and cut-outs, which means that their underlings should be followed. One should assume that if they're an official delegation from a country that doesn't trust you, they might well have anti-scrying magic to keep their private conversations private... But their minions most likely won't, and you'll have much more manpower to assign to keeping tabs on them than they'll have available, so assuming your kingdom has any kind of intelligence personnel or organization it shouldn't be too hard to keep everyone under full-time surveillance.

 

[BoldItalic]

Don't invite them to your city at all. Hold your diplomatic meeting in a remote castle near the border where they can't do any harm. Set spies on them inside the castle, for them to counterspy on. Set traps in disused corridors for them to disarm. Leave baubles lying around for them to steal. Ensure that the castle is heavily guarded "for their protection". They aren't stupid, they know the diplomatic game as well as you do.

 

[ammulder]

So far, I'm not convinced that there's a real magical solution. Alarm and Illusion and the like have duration/concentration issues, and there are so many windows and doors on the castle/palace alone that you'd be blowing an unbelievable amount of magic on a daily basis. I don't see it.

I have to think any diplomats will have protection from mind magic (thought reading, charm, dream invasion, etc.). Even "barbarians" must have managed this if they conduct diplomacy at all.

Holding the meeting in a remote castle is an option, though all else being equal, it strikes me as not the first choice. On the one hand, moving the king with appropriate retinue is a pretty substantial undertaking, and if you have more than one sketchy neighbor, could get annoying fast. And on the other hand, nothing would be worse than letting the enemy diplomats sucker you away from the capital while sending their actual spies to operate freely in your absence. Though, it could still be fine if your summer castle happened to be near the border or something and you can just arrange the invitations for when you'll be there already.

Another concern with alarms and the like is that you don't know what the spies might attempt to do. You can obviously protect the crown jewels, but what if they're trying to tunnel into the dungeon from underneath the castle to release a political prisoner? Or meeting the head of the thieves' guild to offer a big reward if he helps depose you? Or meeting a priest of a forbidden religion? Or fomenting resistance in the slums? Or disrupting the rituals fo a helpful religion? Or killing your political opponent so it gets blamed on you? There are like a bajillion things, and you can't guard them all (with magic or folks).

So I'm still most in agreement with trying to keep the diplomats busy and then using your staff/adventurers/etc. to spy on them and any staff they brought. It only takes them one successful use of Greater Invisibility, but I guess if one slips the net that's when you go to Locate Creature and etc. The PC SWAT Team stays on call for the duration.