How can I present an "unsolvable right now" puzzle without frustrating my players?

Question

I think me and my players are quite fond of puzzles in our TTRPGs, me designing them and they solving them. Last session I presented them with a puzzle that was unsolvable “at the moment”. I thought that they had sufficient foreshadowing about that condition, and at the moment decided not to “backseat play” their game and let them to their devices. Which was very frustrating for both parties, and now I see I should’ve let them know clearly and directly that what they needed wasn’t available right then, we could have kept on playing instead of banging our heads against the wall.

This bad decision aside, I’ll explain the puzzle and their situation:

Situation

They had contracted a sketchy Skyship captain to fly them to another continent, but he asked as part of their payment that they completed a task for him. Middway through the ocean there was a temple to Nemesis (we use greek gods in our campaign), that was one of the clues in a treasure map. They had to get through it and get a treasure that was on the other side.

This is the second temple to Nemesis that they had found, but in the first they never encountered the puzzles that opened the inner chamber (Instead one of the PCs stole everything that wasn’t bolted and angered the Goddess).

In this second temple, they found several traps that summoned Driders if triggered. They quickly found the way through it to the other side, but this time they also found the puzzles to the inner chamber.

The puzzle

The first door had a brazier with an engraving that read: “Blood of the petitioner”

They know, thanks to previous encounters with the goddess' avatar, that she is a very easy to anger goddess, but also very personal and intimate, and just in her decisions. Whoever started this puzzle would be the one needed to finish it, this I directly told them.

The party decided that “the petitioner” should be the character that had angered her, because “best case scenario” Nemesis forgave her, "worst case scenario" the goddess was already angry so nothing changed.

The Character poured a few drops of blood on the brazier, the door opened and they proceeded, killing a few Driders that disappeared and left no trace whatsoever when killed (they were summoned magical constructs).

They found a second brazier, that read “Blood of their friends”. There was also a mural that depicted Nemesis sacrificing her best friend while everyone watched. They tried to use the Captain’s blood, and it didn’t work. She suffered some backlash damage (10 points, just to discourage trying to fit anything in the brazier without thinking), and I told her that as far as she knew Nemesis, she had allies and grudges, but only very few Friends and Enemies, as those words were reserved to personal, intimate people. Then they tried with the blood of one of the other players, which are friends, and it worked.

I thought I had established here that “random friendly person” and “random unfriendly creature” would not qualify.

They found the third brazier, that read “Blood of their enemies” with a partner painting of Nemesis killing Hades (which in our world is her enemy, and they know that since it's kinda centric in the story).

Now, the Character that had been doing this has a personal enemy, someone that stole all her things and sold her to slavery.

I thought they would understand that they needed to find THAT enemy.

Instead they activated some Drider traps on purpose to have their blood. When they killed them I explained again how they didn’t leave anything behind when killed, so then they tried to kill one while it was standing on the brazier… wich they accomplished somehow with very lucky dice. It didn’t work either.

Then they started throwing things at random, several trophies of previous hunts, vials of acid collected from monsters… everything. They resorted to heal her so they could try more things.

In the end they left frustrated. I think, justly so, because I should have stopped and said: It’s not working, think it better. Or “go on with your lifes and come back later”

After much prodding on their part I decided to tell them how to solve the puzzle (now that they are away, and accomplished their main mission), and they felt like it was impossible for them to get to that conclusion and the puzzle itself was unfair.

Actual question

Let’s take out of the equation the fact that I should have interrupted them when they started thrashing at random.

How could I have presented this in a better way?

Answer 1

I, myself, usually run puzzle-heavy adventures. Some of the puzzles are intended to challenge the players, while others are intended to challenge the characters. I am not sure which one you are looking for, but let's try to answer it anyway.

For similar situations, I have had puzzles that were simply not solvable. I'm also a blood-loving person, so, as an example, there was a puzzle in a ruin from old civilizations that required blood from a race that was long (>200 years) extinct. Without Wish, AFAIK, that was impossible. In my case, that made sense for me - they were exploring something made ages ago, time passed, things changed. The puzzle was not impossible when it was made - it is now, and it will probably be forever from now on.

I will split my answer in OOC solutions and IC solutions.

Out of Character solutions

Align your expectation with your players'. This seems a problem of players thinking everything you put in their way is a challenge they can immediately beat. This is not your expectation. Align it.

You can, from the beginning, explicitly state that there will be puzzles that can not be solved, either immediately or ever, as my example above. This is usually done best in the first session. Doing it in a session you will be presenting a puzzle might harm more than help - they could associate you telling that with the puzzle that you are presenting now and immediately think it is not possible to solve without even trying. In one of my campaigns I did that (telling them during a random session, because I forgot to tell it during the first one) and they gave up on solving a puzzle that was actually supposed to be easy. On the other hand, when I present that information from the beginning, they actually try to do it - and when they fail too many times, they give up. Note that they might give up in a solvable puzzle, but that's okay (for me, at least) - people give up from problems they actually could solve all the time. If this is a problem for you, you can still apply my solution and then solve the "giving up from a solvable puzzle" problem - which, from my experience, is easier to do, mainly in character.

If your players simply don't want things they can't immediately solve, either don't present it to them, or, if you really really want to use this mechanism, it might be best to find another group which fits your expectation better.

Also, you could, as you said yourself, just stop them when they have tried too much, OOC, and explain them that. I would not, however, present the solution as you've done, it seems. I would just tell them "Guys, you can't solve it for now. Think better about it, leave and come back later."

In Character Solutions

It is similar to the Out of Character solution, but instead of communicating through speaking OOC, you can communicate in game.

Communicating that there will be unsolvable puzzles is easy. My earlier example was enough for my players to understand that without me saying anything. I was asking for the blood of a race that doesn't exist any more. They went around asking about that race, discovered it was extinct. They went around trying to find a (conserved) blood sample, they couldn't find, obviously. They realized it was an immersion tool, not a mechanical challenge.

Using an NPC (the Captain, it seems) to tell them "Hey guys, you have been there for a while, you tried lots of things, are you sure you want to keep doing it? It seems you are tired. Take a break and let's think about it better." and then giving more tips "Well, if my blood didn't count as a friend, then probably random enemies's blood won't count as the enemy. Is there anyone you really hate?" - if he didn't know the story already. If he did "What about that guy that sold you to slavery?"

Note on how the challenge was presented

As Dronz already mentioned, it seems you put this puzzle in a distant, hard to reach island, similar to the last Tomb Raider movie. That strongly indicates to the players that the puzzle should be solvable in one-go. Unless that enemy is in this island, I would probably have gave tips about the inviability of proceeding there before they even went to the island. I can't suggest how to do that for you without running the campaign itself, but it is certainly something I would have worried about when creating the adventure. If I'm wrong and there are other motivations in the island besides the temple/puzzle, forget this section.

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Although I'm not familiar with ToA for D&D 5e, it seems (from this question) it presents an unsolvable puzzle. It seems (again, from the question) it presents it in a bad way, though, but you might get insight from experienced adventure publishers there.

Answer 2

Fake meritocracy

You have a bunch of other really wonderful answers but I wanted to suggest a completely different improvisational tool that can be used to introduce hints.

It goes like this:

Alice: YES! We sacrificed the drider!

GM: The drider dies on the brazier, and nothing happens.

Bob: What?!

Alice: All that for NOTHING?!

Bob: Hey what's the deal?

GM: Well there's something that not everyone would know. Can I get a history check, difficulty 10? From both of you, but the cleric can take advantage.

(Just for the sake of argument, Alice rolls 8, Bob rolls 7)

GM: Hm, 8 is not quite good enough, but it's close. Alice I will tell you that you can definitely tell that there's something wrong with the wording here, it's old-timey, but you can't quite put your finger on it. Do you want to communicate that to the rest of the party?

Alice: Sure, I tell Carol and Dylan.

GM: Cool, then both of you can take a stab at it, too.

(Dylan rolls a 2, but Carol rolls a 13. If you still have no success and you have an NPC you can fake-roll and fudge their numbers if you desire.)

GM: Great, 13 is good enough. Carol, once Alice points it out to you it's just plain as day. You know that in Old Common, driders would not be your "enemy", they would be foes. Your enemy is, like, your mortal enemy. So like on the engraving on the wall, Nemesis had many foes but Hades was her true enemy. This brazier needs to be filled with the blood of someone much more personally connected to Alice, someone who she hates, and who hates her.

Of course you're just trying to deliver some exposition or a hint, but by phrasing it as something that not everyone would know, you save the broken immersion by rewarding their diligence -- or you create a circumstance where they know that there's something that they don't know and are working on knowing it. The frustration can be turned into forward momentum.

Answer 3

Your feedback to the player’s incorrect attempts—e.g. telling them that the Driders left no remains and thus cannot be sacrfised to the brazier—is misleading.

That particular rejection of their intended solution makes them think that the problem lies in not being able to offer the sacrifice, rather than the identity of the sacrifice itself.

Think this way, if the Driders were some other monster who did leave behind remains, and they players put that in the brazier, they’d immediately know that it’s the particular sacrificial offering that isn’t good enough, and start thinking what would qualify.

In general, your feedback to unsuccessful attempts at a puzzle should respond directly to the part of the intended solution that went wrong. (You might even have the braziers spit out bad offerings in a fiery explosion or have disembodied voices remarking that the petty strife between adventurer and mobs does not qualify as true enmity.)

That being said, specifically informative failures rarely appear in reality, but clearly, that kind of failure is not conducive to enjoyment in your particular game.

(First time answering here, please forgive any stylistic anomaly)

Answer 4

You've established a pattern of presenting them with a world where immediately solvable puzzles come their way, and then varied that pattern by making it unsolvable then, without making that clear. There are various ways to avoid that, including establishing by clear previous example that there are puzzles that can't be solved, or not immediately, or just telling them OOC from the beginning that there are such puzzles, or agreeing that the GM can/should give OOC information that a puzzle isn't solvable at a point in time.

However, in my experience, even many puzzle-oriented players enjoy having puzzles occur naturally and with in-world clues as to whether/how to solve something. In this case, you put it on a special island location that takes a sketchy airship captain to get to, which to me might tend to indicate that hopefully it's not going to require you to somehow get back there (since doing so might become impossible or at least quite inconvenient).

I have run into similar situations where I expect the players to figure something out from an environment and they pursue wrong avenues for a long time. In your case, your clues seem reasonable, but never underestimate the ability of players to miss or make different meanings out of your clues. It can be challenging if you have a goal of not giving the players un-natural OOC hints about what they should do or not do, especially if you want there to be puzzles that involve the players figuring out for themselves that something apparently unimportant is actually a clue. My own favored approach is to have a world with many interesting things that could be investigated and figured out, but nothing that needs to be figured out. That is, I GM to be ok with whatever the players do or don't figure out, and I establish that sort of expectation. (In that context, I and most of my friends enjoy the times players have gone to ridiculous lengths on the wrong track, or have failed to ever figure some things out. The players then develop the skill and responsibility for deciding when to give up investigating something, instead of blaming the universe for not being full of solvable puzzles just for them. But that's a different style of play than you've got going.)

I think though that in the case of your puzzle, it could have been modified to be clearer. Nemesis is already giving clear clues and instructions, including active reactions such as the damage for putting something wrong on a brazier. Other details of the same sort could make it clearer and prevent excessive tries, such as having the temple seal itself up for a week on a failed sacrifice, or having the temple only open up one hour per day or week, so they have to move on. Or have an attendant priest or whatever spiritual presence is judging the sacrifices and giving damage, give a more directly informative message about the nature of the failure.

Other semi-natural methods for delivering clues and/or setting expectations include NPCs that happen to have insight or information, and tales spoken by NPCs or written wherever, that mention other people trying to solve puzzles where they failed, or had to go somewhere else first, or describing what the purpose of that temple is.

Answer 5

Be more specific. Enemy in general means anyone who had ill will towards me, which does not seem to be what you meant.

I might have said the blood of my mortal enemy. Or some other turn of phrase to signify you mean Enemy with a capital E, and not just any run-of-the-mill hostile entity.

You then conjoined your earliest error by making having the spiders leave no blood behind. I would have let the adventurers collect some spilled blood and then had nemesis avatar appear to the party and sneer at "the paltry offering given from the blood of foes not a fortnight met", or some other way to imply that the players need to get the blood from a long-term adversary rather than a mere minion whom they have no grudge against.