"Ah, nevermind," Fionna said, heading out. "It probably wasn't anything important anyway. Let's just go: first stop, Breakfast Kingdom!"

"All right!"

They laughed as they headed outside, to the pretty pristine air, and resumed running across the plains and, later, forests. With their pace, they had made a pretty good distance by the time the storm hit three minutes later, catching them entirely out in the open.

"There's a cave over there!", Flame Prince pointed. "We can take shelter there until the rain is done with us."

As they took cover inside the cave, the rain turned out to be instead knives, striking down and staying up in the grass ground right outside. It was a pouring storm: going out there would be suicide for Fionna, but apparently not for the Flame Prince.

She was about to make him prove it when they noticed that the cave continued on deeper, and decided that they had more important matters in their hands. Even if the rain disappeared to nothing right at this very moment, they would have an exciting cave to explore before breakfast time!

It ended up pretty dark and cold pretty soon, but thankfully Flame Prince was made out of fire, so it was never an issue for either of them. A little bit more of an issue was that it also got kind of narrow and bumpy, and they nearly tripped more than once - which easily got dangerous if Fionna happened to fall towards FP.

But it was all made totally worth it once they found what was at the end of the tunnel: "A dungeon door!", Fionna exclaimed, her mood instantly lifted.

The double door was made out of wood and stone, and was quite decorative and elaborate overall: clearly a lot of care had been put in its construction. There were runes written on its outer edges: "The Chamber holding the Keys of Time and Dimensions," they read. "They are very dangerous. Do not, I repeat, do not, try to use them, or preferably even claim them. To open this door is to invite doom and destruction: do so at your own risk."

They opened the door and entered.

It was a pretty dark place, all over littered not with bones like in the last dungeon, but rather - to Fionna's delight and Flame Prince's chagrin - keys. The floor and alcoves were full of them, of different sizes and shapes, literally hundreds of keys, keycards, magical keystones, tokens, remote car keys, and other types of tools made for opening doors and chests and other things.

And of course, there were things to open them with, too: many boxes and chests of varying sizes were displayed for them, each locked with a different type of a key, keycard, or token. There was not a single piece of wall that was not also a door - indeed, even the floor and ceiling were made of doors!

"Oh Glob oh Grod oh Gob...", she squealed. "I-I know this is going to be really boring to you, but... can you please not burn it all down right away? This is like, like the ultimate dungeon or something!"

Flame Prince just sighed, and graciously lit up the torch offered to him without Fionna even needing to ask. "You've got one hour. After that I'll take over. Like the last time."

"Got it!" Fionna leapt over to the pile of keys, happily, and looked through them to find something that would open something else. The doors all ended up containing rooms and corridors, again entirely made out of more doors openable with some other keys she could find feom elsewhere. The chests contained either minor treasure (gold pieces, bits of armor, minor magic items she didn't know how to use, etc.), even more keys, or were actually a mimic looking to eat her.

Any monsters they found were shaped or otherwise themed after keys and doors, all fairly easy to dispatch and carrying more keys on their person. The traps were a bit more deadly, but all of them could be unlocked and disarmed safely with the use of a key or two. Naturally, every single key snapped and broke as soon as they had managed to use it once, but seemed otherwise indestructible.

"Dungeon crawl,
it's the greatest crawl of all!
No crawl's too small..."

Flame Prince did not join the song.

Finally, the doors contained more runes, all of them to do with keys and time. They seemed to tell a story of their own, but it was pretty hard to make up as the two crawlers had gone to it in such an erratic and unscientific way, nearly always getting them in the wrong order. They spoke of time displacements, Choices (with a capital C) that could split a person in half and create divergent timelines, keys that could unlock the way across dimensions, and assorted cryptic nonsense. According to one, the very fact that this dungeon was accessible to begin with, instead of being safely tucked away to some bubble dimension between time, signified an approaching and inevitable doom.

"The key that opens a thousand locks is a master key, but a lock that is opened by thousand keys is a really poorly-made lock...", Fionna read out loud. "What is that even supposed to mean? Besides the obvious thing."

Flame Prince just shrugged. "Dunno. Your hour is nearly up, anyway."

"Hmm..." Fionna had an intriguing key on her hand, and she was pretty sure it fit to the very interesting-looking chest from before. And she still had several minutes of time. In the end, though, she shrugged and gave Flame Prince his permission. "You've been pretty awesome to tolerate me for this long. So, go ahead."

She knew well what would come next, and so, as her boyfriend moved forward with a fiendish grin on his face, Fionna herself stepped back and well out of the way to let him do his grim job.

It did not take long before the entire dungeon was reduced to an inferno of biblical proportions. Doors and gates were blown apart, chests and their contents melted away, the monsters ran around shrieking as they were consumed by flames - and in the middle of it all, like an ancient nexus of burning destruction, a small sun far too close to the planet, stood the Flame Prince, laughing.

"I am the prince of the Flame Kingdom!", he issued his challenge, "here to burn down the miserable hovel you call a 'dungeon'! Anyone that does not wish to burn with it, flee from my flames and hide into the little holes like the rats you are!"

They rose up to defend their home like the goo skulls in the Vault of Bones, and like the goo skulls, all were quickly incinerated. Anything that was left decided to bail it and stay out of his way. Fionna had a bit of a difficult time navigating across the burning, collapsing corridors, doors that functioned as the floor threatening to open under her, half-melted.

But at last, after scorching their way through many doors, many corridors, and countless key guards, they arrived into a larger chamber. It had no more doors in it, just runed walls, and at the other end, an altar with a chest on it. The chest was large, elaborate, and had three keyholes.

"Hmm." Flame Prince had calmed down significantly by now, his desire for destruction extinguished for the time being. "I guess I could easily open this one too, but want to give a crack at it? I think it's your turn again."

They spent the next fifteen minutes trying every key Fionna had (which was plenty) on each of the three locks, in the end successfully opening two out of three. Instead of going back to the burning dungeon for the third key, she just let Flame Prince burn through it.

Inside there were more keys.

"You have...", Flame Prince groaned. "...got to be kidding me."

"Hold on, I think these are different somehow..." Fionna tried to pick one up.

There were three keys in total, all of them larger and more detailed than the others they had found so far, and felt tingly in hand. The first was pure white, with little rabbit ears coming out of it, and Fionna picked it up just fine. The second was red-orange, looking like it was carved out of a flame, and she could not lift it or make it move at all - but Flame Prince could. The third, light blue and apparently made out of ice, was cold to the touch and would not budge no matter how much either of them tried.

"Huh... I wonder who that one belongs to," Fionna mused.

There was also a map. A surprisingly up-to-date one of the world of Aaa, or the Ice Kingdom in particular. It had more stuff written on it: "Have your key, the one that has been displaced out of time. Here is the place where you will put it to use. Try and be responsible with it."

"Hmm..." She examined the key she had picked up, looking it around. "...I just wonder what this whole 'displaced out of time' bit means. I don't feel any different."

"Ehh," He said. "I just hope whatever these things will open will contain something more worthwhile."

"Yeah. And that we won't need that last blue key to anything."

"Yeah."

They left, and found that the knife storm had dissipated in the meantime. This was a good thing. Neither of them noticed the shadow that passed them by as they left, and the hand that grabbed the remaining key...