The Two Doors Puzzle

Added: 2026-05-07

[00:00:00]One of us tells the truth. The other always lies. One door leads to your quest. The other to your demise. You may ask one question to claim your prize.

[00:00:17]Wait, I don't get it. Was one of you lying just now? This doesn't make any sense. No, the whole lying thing didn't start yet. None of the setup counted. So then, right now one of you was lying.

[00:00:31]But how can that be true if both of you said that the setup didn't count? No, this is still the setup. The puzzle doesn't start until you ask your question. But I've already asked more than one question. Do you even know how your own puzzle works? Yes, we know how it works. It was our idea. Nah, it was really all you. You're the one into logic puzzles. I just gave a few suggestions on the rhyming parts. Aw, hey, thanks. I'd give you a hug right now if we had arms. We could do so many if we had arms. Uh, hello? I'm still here. Look, we are just enchanted doors.

[00:01:09]We can't actually see what's on the other side. It doesn't matter which one you pick. We both lead to the same place.

[00:01:18]What we need [screaming] is a third enchanted object, an impartial third party to do the whole setup part. We'll have to wait for a wizard to wander by and ask him for help. Maybe we should just write the rules down and have the adventurer read them we speak. Nah, that'll never work. [clears throat] Why not? You know, the whole no arms thing.

[00:01:38]>> [sighs] >> Ah, right.

[00:01:41]Okay, let's see. One of us tells the truth, the other always lies. One door leads to your quest, the other to your demise. You may ask one question to claim your prize. Hmm, is this a sword? No.

[00:01:55]>> [laughter] >> This is so easy. You're the liar, so I choose this door.

[00:02:02]Why do so many of them assume the lying door leads to bad things?

[00:02:07]No idea. Humans are so weird.

[00:02:12]One of us tells the truth, the other always lies. One door leads to your quest, the other to your demise. You may ask one question to claim your prize.

[00:02:20]Oh, this is easy. How many fingers am I holding up? 12.

[00:02:24]>> There, liar. Okay, door number two.

[00:02:27]Which door leads to safety?

[00:02:30]You idiot, you only get one question.

[00:02:33]What? Pay attention. I just read the rules. Wait, do I also get to ask a question? Yes. Haha, yes.

[00:02:42]Oh.

[00:02:44]Well, at least we are both idiots.

[00:02:48]One of us tells the truth, the other always lies. One door leads to your quest, the other to your demise. You may ask one question to claim your prize.

[00:02:57]Huh, there's nobody here.

[00:02:59]I guess I have to wait for the guards to come back.

[00:03:01]>> We are the Sorry, we didn't mean to frighten you. Oh, wow, sentient doors.

[00:03:07]Amazing. Well, I wouldn't. I mean, we're just doors. Certainly the most impressive doors I've seen on my quest.

[00:03:15]What other doors have you seen? Oh, just the regular stuff, you know, big stone ones that have a hidden lever you pull so they drop into the ground, creepy ones that are like a hundred skulls tied together, ones that are made of fire and you have to drink the right potion to go through without burning up. Pretty much exactly what you'd expect, but none of them could hold a conversation. I don't think I've talked to anything intelligent for days. Wow, you think you've been in this dungeon for many days? Yeah, it's hard to tell without being able to see the sun. I think I've been going in circles for a bit now.

[00:03:46]There's this one hallway that kind of oozes this purple slime that I saw some rats licking, so I tried it and wow, it's actually it's actually pretty tasty, so I've been going back to get more slime each day. It's all I've been eating, it's all I've been thinking about. To be honest, really, I kind of forgot why I'm in this dungeon. Do you know why I'm here?

[00:04:03]Yes. Oh, that's great. What am I supposed to do?

[00:04:08]Oh, dang, the riddle thing. I forgot.

[00:04:12]Oh, [sighs and gasps] dang it. Well, shoot. I guess I should go back to the slime hallway.

[00:04:20]The part about the fire door was interesting. Yes, he's never mentioned that before. It is fascinating that the longer he's been trapped down here, the less time he thinks has gone by. Yeah, I think we will only get a few more visits before the slime has totally taken over his brain.

[00:04:37]One of us tells the truth. The other always Hmm.

[00:04:42]Hmm.

[00:04:47]What is it? What happened? Oh, wow, I think I fell asleep and forgot to lock myself. I told you you got to lock yourself every time. Right away. If you're closed, you're locked. I know, I know. You're right. Why were you yelling? I was having this really weird dream. I wasn't in a part of the dungeon that any adventurer had described before. It was green all around and blue above. I was also blue. I was the door on a small blue box. There were a bunch of us there. Humans kept going in and out of the doors. But then, something happened. Someone opened one of the doors across from me while another human was still inside and I saw What did you see? Horrible things. Worse than what we've seen down >> Horrible things.

[00:05:35]What does it all mean? It means keep your door locked.

[00:05:38]>> Are you locked right now? Yes.

[00:05:42]Yes.

[00:05:45]One of us leads to your quest. The other two lead to your demise. Okay, middle door. If I ask the first door which door to open, what would they say? Well, I don't This isn't a question puzzle. You just pick one. It's just random chance.

[00:06:02]No skill involved? Hey, don't get mad at us. The dungeon master was getting a lot of complaints that this area was taking too long. It's been kind of a bottleneck. So this is to speed things up. I don't know. It's kind of disappointing that I got so far in this dungeon and now it just comes down to a one in three chance. Please, just make your selection. There's a line forming behind you. Fine. I'll take the middle door.

[00:06:26]But wait, now that you see the third door was death, do you want to keep your choice of the middle door or switch to me? Why would I switch? I don't have any new information. Instead of a one in three chance, it's now just a fifty-fifty chance.

[00:06:40]You do have new information. Door number three was bad. How does that help me?

[00:06:46]It's still just a coin flip between the two doors. No, you got to remember that I know which one is the good door. When I opened door three, I knew it was one of the bad doors.

[00:06:57]>> [sighs and gasps] >> This really just feels like you're trying to trick me. Do you get like a commission or something for the number of adventurers that are turned into skeletons? Do you have like a secret bone business on the side that I don't know about? Look, I got to admit I'm kind of on their side. I don't see how you opening one door does anything useful. It's still just a fifty-fifty shot. How is this speeding it up if we have to go through this big long explanation every time? Come on, we went over this during orientation. Just imagine there's 1,000 doors. The human comes up and picks door number 11.

[00:07:30]We then open 998 of the other doors to show they were bad. So there were two doors left. Number 11, their first choice, and number 73. Out of 1,000 doors, did they happen to make the correct choice on the first guess or should they switch to the only other door I didn't open?

[00:07:51]Oh, I think I finally get it. They should always switch. Yeah, I guess the trick is to remember that you always know which one is the good door. It's not a random chance for you. Yes, exactly. So, as I was saying, do you want to keep your first selection or switch to me?

[00:08:14]Oh, dang, they left.

[00:08:16]One of us leads to your quest. The other leads to your >> Oh, hey, you two. Nice to see you again.

[00:08:24]You don't need to go through the whole routine every time I walk by. You remember us? Sure, I helped you write that scroll ages ago and you helped me find my way back to the purple slime hallway. You have new clothing. Yeah, I made this out of some drapery from the false throne room. People are always so excited thinking they're going to get treasure there. You think all the bones in the corner would tip them off? Didn't you have a third friend down here with you? Yes, that was just a temporary assignment. They got moved to the fourth level after a few months. I believe they are guarding a wine cellar now. Oh, wow, we have a real wine cellar down here?

[00:09:04]No, no, it's all various poisons and foul-smelling liquids.

[00:09:10]>> [laughter] [gasps] >> This place is hilarious. Oh, I hear some fresh adventurers coming, so I better get out of sight. Okay, see you next time. Bye. Wow, I didn't see that coming. Yeah, their memories are returning. I never realized the purple slime could sustain one of the human visitors. I know. Everything else is so dangerous.

[00:09:36]One of us tells the truth. The other always lies. No, I don't. Don't what?

[00:09:43]You called me a liar. No, I didn't. I said one of us lies. That could be either of us. You totally implied it was me. That was mean. You said you were tired of this speech and so I offered to do the whole thing myself. What else am I supposed to do? Well, maybe what you're supposed to do was not let the rats steal our scroll. How?

[00:10:04]How was I supposed to stop a rat? By grabbing them with my arms? Oh, that's right. We're doors. A loud sound. A quick slam. You could have opened really fast and the motion would have scared them away. Yeah, that's a good point.

[00:10:18]They are skittish like that. That probably would have worked. Right?

[00:10:23]That's all that I'm saying. I'm sorry.

[00:10:25]I'm better when it's my turn to be on lookout. I panicked. I'm sorry that I was asleep when the rats came.

[00:10:32]>> [snorts] >> We're better as a team. Why do they even make us need sleep anyways? We're doors.

[00:10:38]What's the point of sleeping doors? As if that's the weirdest thing about this place. So, I'm going to go.

[00:10:47]One of us tells the truth. The other always lies.

[00:10:52]One of us leads to your quest. The other to your demise. You may ask one question to claim your prize. I'm sick of these places with their novelty restroom doors. Just mark things clearly so people don't rupture their bladder trying to solve a logic puzzle. No, we're not restroom doors. We fulfill your quest. Yes, I know how it works and right now my quest is to find some place to pee before I resort to using one of my boots. I really like these boots and hope to escape from here with them.

[00:11:29]Seriously though, we are not the doors to the restroom. We guard like treasure, probably. Or perhaps some sort of cool magical artifact. Something like that. Look, I paid a two-headed crow three shiny stones to draw me this map and it clearly shows that at the end of this hallway Oh, wait.

[00:11:51]I'm at the wrong end.

[00:11:53]>> [laughter] >> Sorry to bother you.

[00:11:55]Do you think maybe they were right?

[00:11:57]If their quest was to find a restroom, why wouldn't that be what they found if they chose the correct door? Huh.

[00:12:04]I guess we'll never know.

[00:12:06]Come [snorts] on.

[00:12:11]One of us leads to your quest. Oh, hello again, you two. Oh, it's you. Yes, I guess I haven't been by in a while. I suppose I look a little different. Did you find a new source for your purple slime? No, I have not.

[00:12:29]I fear I may never find it again. But, I have learned a great many things in my quest. Ooh, anything about repelling thieving rats? No, but I did learn this.

[00:12:45]What?

[00:12:46]My hinges moved? And also this.

[00:12:52]Arms?

[00:12:53]We have arms? You are the wizard we have always dreamed of. How can we ever thank you? No, no, there's no need.

[00:13:03]But, now you can thank each other. What do you mean thank? Oh.

[00:13:10]Our arms.

[00:13:13]Ah, wait. My slime?

[00:13:18]Of course.

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