Something wasn't right here, he could feel it.

All three of them had agreed to a moment of relaxation near one of the waterfalls. But Dart hadn't shown up yet. And that made Ruffrunner worried.

Dart was never late for anything, not even for a training session. The youngest Night Light was aware that Dart would sometimes fly off for a moment alone… but he had a feeling that wasn't the whole story.

Pouncer had gotten impatient and sent Ruffrunner off to find their sister. Instinctively, the Night Light's first thought would be that she was taking a longer nap than usual.

He landed at the entrance to her sleeping cave and peeked inside. Only a few bioluminescent mushrooms were in there, but they tended to dim every once in a while. Right now, they weren't bright enough to give Ruffrunner a clear view.

"Dart? Hello?" he whispered, slowly advancing inside. No response came. He sighed.

"Dart, wake up," Ruffrunner said, looking around the cave. "Pouncer and I have waited long enough. Come on."

Still nothing. The Night Light investigated the cave… only to find out it was empty. His sister was nowhere in sight.

"Great, Ruffrunner," he muttered to himself with a groan. "Now you've gone and wasted more time. What were you thinking, believing she was going to be… here?"

A medium-sized boulder caught his eye. Normally, he'd dismiss it, but… was it just him or did it seem a little out of place?

Then again, he'd never been in Dart's cave before. So why had he never thought of it before?

And maybe Dart wouldn't mind if he had a little look around.

Prowling up to the rock and placing his head against it, Ruffruuner pushed against it with a grunt. Surrendering to his strength, the boulder was moved aside… and a hole large enough for a dragon like him to fit in rested just behind it.

A tunnel? Did Dart know about this? And what was on the other side? Ruffrunner wasn't sure if he wanted to find out… but the youngest Night Light's curiosity got the better of him.

Maybe just a little glimpse. He told himself. Crouching down, he squeezed himself through the hole and moved down the tunnel. There wasn't much light, but Ruffrunner navigated easily through the darkness. For once, he was glad his father's near-forgotten species had night vision, which had passed on to him and his siblings.

A faint glow shone from the end of the tunnel. But to Ruffrunner's confusion, this didn't look like mushroom light or sunlight from holes that allowed it to shine down into the dragons' home. This was something else. And if he was right, it appeared to be in different colors.

The more he crawled through the final stretch of the tunnel, the brighter the light seemed to be. Ruffrunner squinted as he stepped out from the tunnel… and his eyes adjusted to the chamber before him.

"Whoa…"

Bioluminescent mushrooms around the rim of the chamber had their light reflected off the main focus here: a large pile of multicolored crystals organized like a miniature hill. The mere sight of it made Ruffrunner's mouth hang open. It was… beautiful.

But the only crystals he knew of were in a series of caves farther underground. All kinds of gemstones could be found there, from emeralds to sapphires, from rubies to opals, from amethysts to topaz, and even obsidian and diamonds (although they were rare).

Had Dart known of this, maybe even discovered it? Ruffrunner ignored any questions he had, his eyes unable to move away from the heap of gemstones. Maybe if he took just one for himself, it wouldn't be noticed.

Creeping up to the pile, Ruffrunner locked his eyes on an emerald gem at the bottom of the pile. That looked good enough for him. Slowly, he reached out with his front foot and gently wrapped his claws around it. He looked up at the rest of the pile.

One false move and it could come crashing down on top of him. He needed to be careful.

Closing his eyes and feeling his heart race, Ruffrunner took a deep breath…

...and swiftly swiped the emerald away from the pile.

He stood completely still, the green gem tucked away safely in his claws. He opened one eye… and exhaled in relief. The pile hadn't collapsed. All that had changed was a ruby falling to where the emerald once lay. Ruffrunner sighed happily, turning to the tunnel with the green crystal in his possession…

...and froze in terror when his eyes rested on Dart standing right in front of the tunnel.

And she looked absolutely furious.

A shiver ran down Ruffrunner's spine. He'd never seen his sister act this mad, but her unnoticed arrival was not a surprise. After all, the three of them had been trained in both combat and stealth ever since that visit to New Berk when they were hatchlings.

His sister's cold stare from her ice-blue eyes brought Ruffrunner back to the present. He could swear he heard what sounded like a low growl.

"Um… hey," he began sheepishly. "I, uh… I was just looking for you."

"Drop it," she snarled, cutting off his words. The rest of his body freezing up at her tone, Ruffrunner released the green crystal. It clinked and tumbled across the stony ground, coming to a stop near Dart's feet. The eldest Night Light placed her front foot on top of it, her eyes never leaving her brother.

"Y-you know, I think I better g-get going now-"

Dart's wings flashed open to their full size in an instant, blocking off the tunnel and once again halting Ruffrunner in his tracks. He was almost certain his sister would kill him here and now. A sense of impending doom flooded through his blood, and he was tempted to cover his face with his wing.

"How…" Dart spoke coldly, her words cutting through Ruffrunner's very soul. "...did you find this place?"

"I… uh… well…um..." Ruffrunner stammered, not sure how he was going to get out of this one. Taking a deep breath and closing his eyes… he prayed for his end to be swift.

"PouncerandIwerewaitingforyouatthewaterfallbutyouweren'tthereandhesentmetofindyouandIwenttoyourcavefoundtheboulderwentthroughthetunnelandIcouldn'thelpmyselfAH!"

He was still. He almost thought he was dead, that Dart had lunged like a predator and snapped his neck. But he could hear his pulse pounding like mad, his blood chilled...and he opened his eyes.

Dart hadn't moved. Her stern gaze was still locked on her younger brother, and her breathing had gone from heavy to controlled. With a calmed exhale, she stepped off the emerald and lowered her wings.

"Dragons don't take well to thieves, Ruffrunner," she scolded him. "Especially thieves who don't know any better."

"Thief?!" Ruffrunner blurted out. "No! I'm not a thief! I didn't even know I was stealing-" Something inside him clicked. "This… this is your crystal pile?"

"What?" Dart asked, unamused. "Were you expecting a message clawed into the rock? Perhaps something along the lines of 'Do not touch or else'?"

"Uh…" Ruffrunner couldn't find the words. But he hated himself for not realizing it sooner. A secret passage that led to a hoard of gemstone in Dart's cave? This was obviously hers… but it still didn't add up.

"Dart, I… I'm sorry," he groaned. "I should have known sooner… but how long have you had this? All those times you flew off alone… were you collecting these?"

Dart huffed, walking up to the pile with the emerald tucked in her claw. Placing it back on the pile, she turned to her brother with a look that said she had some explaining to do.

"It all started when I decided to explore when we were still little dragonets," she began, gently flying up to the top and laying down on the crystals. "As anyone else would be, I was extremely amazed when I found the cavern system full of them. Then I remembered the stories."

"What stories?" Ruffrunner asked her.

"About the dragons who took a liking to treasure," Dart answered, taking a sapphire and staring at it with wonder in her eyes. "They say that those who lived in the mountains were feared by humans, who said they raised on piles of the bones and armor of any warrior who tried to kill them."

Ruffrunner paused, grimacing. "That's… ominous."

"And then there are the dragons who grew fascinated with gold. They gathered everything of the kind, from coins to goblets and even swords, which they prized dearly. But this drew… unwanted attention."

"Let me guess…" Ruffrunner cut in. "Thieves?"

Dart nodded, her eyes never leaving the shining jewel as blue as her eyes. "News of a dragon's hoard would reach humans, who would wish of claiming it as their own. Filled with dreams of riches and glorious wealth, they'd travel to the dragon's lair with equipment they believed would kill the dragon. The dragon wouldn't surrender their beloved stash easily, so they'd fight to the death like a mother defending her nest."

Ruffrunner tried to piece it together. "So… you collected any crystals that looked beautiful enough and kept them secret so that no other dragon would find it and steal from you."

"Yes," his sister answered. "But not because of wealth or for glory."

"Then why?"

"For a little peace and quiet. A little tranquility. And for nights where I can't sleep." Dart replied, resting her head on the gems. "For any crystals I find that I think are a little sharp, I put those on the bottom. Plus… I decided to have a little stash made up of something that's actually pretty. Bones can be uncomfortable to rest on and I don't see what use we have for gold these days."

Ruffrunner stared at the pile his sister rested on. "So… I guess what you said is true, then. You did want a little time for yourself."

"Tell me about it. Breaking up squabbles with you and Pouncer can be exhausting sometimes."

Ruffrunner instantly remembered something. "Uh, hey, speaking of-"

"DART! RUFFRUNNER!" a voice boomed out from the tunnel nearby. "WHERE THE FATES ARE YOU?! WE WERE SUPPOSED TO BE AT THE FALLS AN HOUR AGO!"

His older brother's faint-yet-angry voice made Ruffrunner jolt and whirl back to the tunnel. The youngest Night Light readied a reply… but hesitated. What if he led his brother here?

Not fazed at all by the sound, Dart rose to her feet and stretched out her spine. "Well…" she yawned. "I believe you two owed me a little soak."

"Y-yeah, sure. That's right." the Night Light replied, finding his voice again. Still a little shaken by Pouncer's tone, he made his way to the tunnel… but something bounced off his scales.

"Ow! What-" he stopped, seeing the emerald he had tried to take by his feet. Glancing back, he saw Dart at the bottom of the pile… with a warm expression.

"Go on, take it. I've got more," she said with an encouraging purr. "Just… don't tell Pouncer about this."

"But what if he stumbles upon this place like I did?"

"Oh, don't worry. I'll take care of it." his sister replied, making her way into the tunnel. As soon as her tail left Ruffrunner's view, he picked up the gem in his mouth, making a note to stop by his cave to drop it off and hide it.

Following Dart through the tunnel, Ruffrunner came out of the end and waited for her to push the boulder back into place. Once the two Night Lights made sure there was nothing out of the ordinary, with Ruffrunner placing his emerald in a place he knew would be there when he returned, they raced out of the cave.

Spreading their wings and taking flight, they found an annoyed Pouncer waiting for them on top of a fungi platform. Upon noticing them, the mostly-white Night Light narrowed his eyes.

"So THERE you are!" he growled. "Where in all the realm have you been?!"

"Honestly," Dart answered. "I needed a little break and caught myself up on some old legends."

"Whatever!" Pouncer snarled, turning to take flight. "I've waited long enough for the both of you! Now are we going to the falls or what?!"

Instead of answering her brother directly, Dart turned to Ruffrunner and gave him an assuring wink. Taken aback by this, the youngest Night Light made another note to ask her how she had learned that.

"Race you, Pouncer!" Dart called, running to the edge of the platform and leaping off. As she spread her wings, Ruffrunner took off after her and flapped his own.

"Wha-hey! That's not fair!" Pouncer stuttered before realizing he was caught off-guard and left behind. Jumping into the air, he beat his wings furiously to keep up with them.

"That's because you're losing!" Dart shouted back, laughing as Ruffrunner joined in, the youngest Night Light looping over her to overtake her position.

"Last one there gets splashed by the other two!" he declared, racing off into the Hidden World's lush surroundings with his siblings right behind him. "Woohoo!"

As Dart and Pouncer boasted about their inevitable win, Ruffrunner realized there was a different kind of treasure. One that doesn't have the risk of being stolen so easily. One that doesn't need to be hidden. And one that was with him ever since his hatching.

The treasure of his own family. And just like the dragons of old protected their treasure… he would fight to protect his to the death.

(A/N: I watched Onward Friday on Disney +, and it got me motivated to do something family-related. Then last night I remembered stories of dragons with hoards of treasure (Smaug, anyone?) and decided to write this earlier today. Also, there aren't many stories about the Night Lights, so I see this as an absolute win.)