A Treasure Map Could Be Your Next Adventure Hook

Let's do some quick dungeon math. According to the AD&D DMG, 4 in 20 (or 1 in 5) dungeon rooms contain treasure (three guarded by monsters and one unguarded):

When determining exactly what treasure is in a room, you roll on this table once for unguarded treasure and twice for treasure guarded by monsters, adding 10% to the roll in the latter case:

There is a 3% chance of an unguarded treasure room containing magic items and a 26% chance of a treasure room guarded by monsters containing magic items (13% chance because of the +10% to the roll, times two because we're rolling twice). 

Again, 1 in 20 (5%) of rooms will contain unguarded treasure, and 3 in 20 (15%) of rooms will contain treasure guarded by monsters. Thus, 0.15% of all rooms will contain unguarded magic items and 3.9% of all rooms will contain guarded magic items. 4.05% of total rooms will have treasure containing magic items - roughly 4 in 100 or 1 in 25. Interestingly, while all other treasure types scale with dungeon level, number of magic items does not.

Here's what I'm interested in - 10% of magic items are actually maps. What kind of maps? Treasure maps, of course:

"But wait!" you might say, "This excerpt says 'This system can be used for monsters you place on the outdoor map as well as for monsters randomly encountered by a party exploring the wilderness.' It doesn't say anything about dungeons. And TABLE V.G. above even says to 'Roll once on Magic Items Table' - nothing about maps!"

And you would be right. The MAP OR MAGIC DETERMINATION table likely refers to the rightmost column on the treasure table in the Monster Manual:

These treasure types are typically found only in wilderness monster lairs. Some are found as "individual treasure" (i.e. coinage carried in the pockets of goblins and such), but none of those types have a chance to contain maps.

So there you have it - no treasure maps in dungeons. Except:

This seems to indicate that treasures maps can be found in dungeons. Presumably, when the term "monster's lair" is used in the previous excerpt, it is meant not only to apply to wilderness lairs but also dungeon rooms in which monsters are guarding treasure.

Note that "A map should never list its treasure, only show its location." There will be some guidance later as to where and what kind of treasure the map leads to, but no guidance is provided as to how to actually create a treasure map for your game, "for how can it be possible to direct each DM properly considering the infinite possibilities under which the map will be located?" If you want gameable examples, Phlox has some good ones.

Taking a step back, we know that 3% of unguarded treasure rooms and 26% of guarded treasure rooms contain magic items. Of the guarded treasure rooms containing magic items, 98.31% will contain one magic item and 1.69% will contain two magic items. Considering that 10% of magic items will actually be treasure maps, 0.3% of unguarded treasure rooms containing magic items and 10.169% of guarded treasure rooms containing magic items will contain maps (10% of guarded treasure rooms containing one magic item = 9.831% + 20% of guarded treasure rooms containing two magic items = .338%).

Again, 5% of total rooms contain unguarded treasure and 15% of total rooms contain guarded treasure. 0.015% of total rooms contain unguarded treasure maps and 1.52535% of total rooms contain guarded treasure maps - 1.5255% of total dungeon rooms contain treasure maps. That's 1 in every 66 rooms. If your dungeon is big enough (and particularly if you're aspiring for anything of the "megadungeon" classification), there will probably be a treasure map in there somewhere. I hope I did my math right! I am happy to be corrected.

Note that tricks found in dungeons might also release maps, as found in APPENDIX H: TRICKS:

Treasure maps found in dungeons usually point the way to treasure inside that very dungeon, but might point to "another lost dungeon" or somewhere "along the course of a long underground river."

Let's dig into those wilderness lair treasure types (associated monster types are sourced from here):

• Type A and F hoards (e.g. humans, centaurs, vampires, basilisks, medusae, shadows, rakshasa, rhemoraz, salamanders, leprechauns, and chimeras) have a 9% chance of containing a map
• Type C hoards (e.g. minotaurs, gargoyles, lycanthropes, gnomes, and pixies) have a 2% chance
• Type D hoards (e.g. orcs, hobgoblins, gnolls, mummies, dryads, griffins, chimeras, manticores, and purple worms) have a 3% chance
• Type E hoards (e.g. giants, wraiths, gorgons, and wyverns) have a 7.5% chance
• Type G hoards (e.g. dwarves) have a 14% chance
• Type H hoards (e.g. dragons) have a 6% chance
• Type I hoards (e.g. rocs) have a 1.5% chance
• Type W hoards (e.g. buccaneers) have a flat 55% chance of having a map
• Type Z hoards (e.g. demigods and demon lords) have a 15% chance

Buccaneers, of course, have the greatest chance of possessing a treasure map. There are plenty of genre tropes to draw upon in this case. Demigods and demon lords are next in line. Do the maps in their possession point towards their own secreted away hoards? Dwarves are next, and it's easy enough to imagine why if you're familiar with The Hobbit. But what of the others? Whose treasure maps do these monsters possess, and how did they come to acquire them?

Here's what the DMG says about maps found in wilderness lairs:

Treasure maps found in wilderness lairs can themselves lead elsewhere within the lair (an underground "labyrinth of caves") or to some other location 5 to 500 miles away, which may be buried and unguarded (in the classic way that pirates bury treasure), hidden in water, guarded in another monster's lair, in ruins or a crypt (presumably themselves dungeons), or even "secreted in a town".

In rare cases, the player character might also obtain a treasure map by drawing the Key card from a deck of many things:

Note that treasure maps are written in a cypher. Like a spell scroll, a read magic spell must be employed to decipher one:

This means that treasure maps are also subject to all kinds of trickery on the part of the DM, like curses and traps triggered by reading their contents - explosive runes and magic symbols the like. The text states that "a map will appear magical until the proper spell is used" (emphasis mine), suggesting that the map itself is not necessarily magical.

You can also get your highly-intelligent sword to read the map for you:

Treasure maps come in four types: false maps (which presumably lead to nothing at all), those leading to monetary treasure, those leading to magic treasure, and those leading to "combined hoards" of both money and magic items. Note again that a treasure map should never indicate what it leads to. 

MONETARY TREASURE "is weighted towards large quantities of coins which will require a train to remove - or must be left entirely if foreplanning is not observed":

If not carried away immediately, the DM is encouraged to set a percentage chance that the treasure will be stolen by someone or something else. This is more likely if the treasure was guarded by some other monster, not unlike the Five Armies showing up to claim Smaug's treasure after he was slain. This meshes nicely with my post about treasure as a source of challenge in AD&D, in which the comparison to The Hobbit is made explicit.

Less of an inconvenience will be MAGIC TREASURE, which can be easily carried away:

This table is weighted towards potions, scrolls, armor, and weapons, "so as to prevent imbalance in the game" and to "Keep potent magic items rare." The DM is encouraged to "Increase scarcity by destroying or stealing what is found!"

One might wonder whether the "Any [X amount of magic] items" results might in turn yield another treasure map. I don't think this is intended to be the case, as this possibility is made explicit in the COMBINED HOARD table:

With a result of 81 or higher, you will find the best possible monetary or magic treasure plus a map to either a separate magic treasure or a separate monetary treasure, respectively. Since these are the most valuable hoards, the DM is encouraged to hide them far away and to guard them with traps and monsters. There's something very funny about completing a long and arduous adventure following one of these maps only to immediately come into possession of another.

So what's the point of treasure maps? Well, they're built in adventure hooks! When found in dungeons, they point the players towards some destination within the dungeon or to another dungeon entirely. When found in the wilderness, they can point the players towards some other location in your sandbox or somewhere beyond the current area of play entirely. 

Want the players to go deeper into the dungeon? Give them a treasure map. Want them to visit a different dungeon? Give them a treasure map. Want them to trek out into the wilderness, venture underwater, track down a monster's wilderness lair, or get mixed up in the deadly social fabric of urban gameplay? Give them a treasure map.

If you're flying by the seat of your pants, rolling for treasure as the players find it, a treasure map gives you the chance to detail a new location in which to house the hoard - a fun little surprise for you. It's quantum treasure - even you don't know it exists until it comes into play. Unfortunately, you can't do much with something you don't know about.

If on the other hand you're prepping everything ahead of the campaign's start - including rolling for treasure in dungeons and lairs - then rolling up a treasure map somewhere gives you the chance to hide the hoard from the very beginning. You know there's a massive hoard of treasure buried in an inconspicuous location right beneath the starting town, but the players don't, and they won't know unless they find that map. 

Maybe the treasure hoard is the stuff of legend, and your setting's factions and NPCs are all after it, but no one knows where the map is. Rumor has it that it was lost deep within the dungeon, or that the ancient red dragon counts it among its hoard. The legendary Dread Pirate is rumored to have hidden his plundered goods on one of those steamy jungle isles off the southern coast, but the map was lost when his flagship sunk a decade ago.

Another possibility is that whoever or whatever possesses the map is actively trying to find the treasure. Maybe the evil wizard who rules the town has the map already, but is seeking the means to acquire the hoard their self. A clan of dwarves seeks a burglar to help them reclaim their lost gold. The buccaneers are scouring the coast for something, plundering as they go. What are they looking for? Perhaps the orcs, hobgoblins, or gnolls are harassing human civilization because they know there's treasure buried beneath one of those towns. Perhaps a dragon with a treasure map is responsible for martialing that host to acquire the treasure on its behalf.

Once the player characters have the map, the adventure is only just beginning. They have to plan an expedition into the dungeon, the wilderness, or out to sea. They might have to recruit a caravan of drovers and porters to help them haul the hoard away when they find it. They have to contend with all the usual dangers of the environment its found in, any monsters that guard it, and any traps laid upon it. 

They have to do all of this while somehow keeping it a secret from those same factions and NPCs who are after it, even as the logistics may require recruiting dozens of hirelings or hauling the treasure out in the middle of town right under those same NPCs' noses. Hopefully it isn't a false map. That would be most unfortunate.

Please excuse the pun, but that is a veritable treasure trove of juicy gameplay implications. Go on. What are you waiting for? Put a treasure map in your game right now.