Ninjago, present day

"I can't believe this!" Rocky exclaimed. "Some people lose their dagger, or their mug. Not me—I manage to lose an entire Ninja Pup!"

"For the last time, Rocky," Marshal stated, "Kijo's disappearance was not your fault!"

"But I'm the one who suggested that he work on his flying!"

"We don't have time for this!" Kai interjected. "We've got two friends to find, and we won't be able to find them if you keep—" He suddenly stopped as another portal opened in the sky above the team. Everyone looked up at the strange sight.

"Oh, no! What now?" Andrew complained. But before anyone could answer him, the team suddenly gazed openmouthed as six dragons—all with riders—and a pup came flying out of the portal.

"Look, everyone!" Skye shouted. "It's Kijo!"

"Who're his new friends?" Zuma commented. Just then the dragons started to circle around the dojo to land in the valley below. But Kijo made it to the ground first. And it was he who first saw the team standing there.

"Ninja! Pups!" he cried out, running towards them.

"Kijo!" Rocky, Kito, and Kelly all cried out at the same time, running towards Kijo. He stopped in his tracks just as the three pups suddenly puppy-piled him.

"Um, guys? Air? Please?" he begged.

"Whoops." Kelly exclaimed before she, Rocky, and Kito got off of Kijo and let him get back on his feet.

"Kijo, I just have one thing to say to you." Rocky stated sternly. Kijo flattened his ears back in timidity and nervously stammered, "Y-Yes?"

"Don't you EVER scare me like that again!" Rocky finished.

Kijo let out a shaky laugh and said, "I won't, Rocky. I promise."

Behind him, a boy on a white dragon dismounted and walked over to where Kai was, a rather angry look on his face. "Where's Toothless?! Where are you hiding him?!"

"Toothless? Who's Toothless?" Kai asked, puzzled.

"My dragon—my friend. Where are you hiding him?!"

"If you mean the big black dragon that we just saw take off with Lloyd, then a better question is, where are you hiding our friend?!"

"Wait, stop!" Arin cried out, jumping between the two.

"Yeah, cool your jets, you two. Let's not jump to any conclusions here." Kito added.

At that, the boy and Kai stopped glaring at each other, embarrassed. "Oh, um, sorry, kid. I…I thought you took our leader, Lloyd."

"Yeah, I'm sorry too. I should have known that you weren't the kind of people who'd take Toothless." As the young boy spoke, the pups heard a small squeak from behind them. It was Riyu! He'd followed Everest and Zane down the mountain and was now headed straight for Hiccup. The little dragon leaped into the air, bowled the boy over, and started licking his face like crazy. The boy laughed—Riyu's licks were ticklish. "Who's this little guy?" he asked.

"That is Riyu." Sora answered. "He's our littlest dragon here. Up there we've also got Zanth and Jiro. They're much bigger than he is."

"We think Riyu might be a Source Dragon, 'cause of his Tech Power." Kelly added.

"What's a Source Dragon?" someone else asked. "I've studied every dragon we know of, and I have never heard of those."

Kai looked over to see a blond-haired, rather broad-shouldered boy looking down at Riyu. He must have dismounted when Kai wasn't looking.

"Well, that's kind of hard to explain, Fishlegs." Kijo answered. Several of the pups smothered giggles behind their paws. Fishlegs? What kind of name was that?

Riyu got off of Hiccup, and the boy stood up, dusting himself off as Kijo continued, "I think that Source Dragons don't come from your world. And we don't know much about them ourselves. Just that they might be tied to the Merge, and they're somehow connected to elemental powers." At the looks on Hiccup's and Fishlegs's faces, Kijo was tempted to facepalm. He'd forgotten that none of the Dragon Riders would know about the Merge or elemental powers.

"Don't worry, Kijo." Twinkle exclaimed. "I've got this covered." Then she turned to face the two boys and explained, "You see, Ninjago was once the only thing on the map. But several years ago, Ninjago and all the realms connected to it came together in an event we call the Merge. It changed the face of Ninjago's reality, and we still don't know why it happened. We think it might have something to do with Source Dragons, who are the guardians of seven of the realms. As for elemental powers, well…you gotta see them in action to really understand them."

"Oh." Hiccup said thoughtfully. He still didn't understand completely, but he was definitely starting to see that this realm—or realms, more specifically—were an awful lot like his own.

"Um, Kijo, would you mind introducing us to your new friends here?" Chase asked.

"Oh, yeah. These are Hiccup, Astrid, Snoutlout, Fishlegs, Ruffnut, Tuffnut, and Cassie." Kijo explained, pointing to each one in turn.

"We're Dragon Riders!" Cassie exclaimed.

"Cassie!" Hiccup scolded before saying, "Sorry about that. Cassie tends to be a bit overenthusiastic sometimes. Bit of a hothead, too."

"It's okay, Hiccup." Marshal replied. "Kai here's also kind of a hothead."

"Hey, who you calling a hothead?!" Kai retorted hotly, crossing his arms and glaring at Marshal. The other ninja and pups just laughed.

"Nice to meet you, Dragon Riders." Andrew said after everyone had stopped laughing. "I'm Andrew. You already met Kai, Kijo, and Riyu. The others are Cole, Nya, Zane, Chase, Skye, Rubble, Rocky, Zuma, Marshal, Everest, Tuck, Ella, Tracker, Rex, Sweetie, my sister Twinkle, Gracie, Matthew, and the newest Ninja Pups, Kito, Kelly, Kaida, and Kaiyo." As Andrew spoke, he pointed to each team member in turn, just as Kijo had done with the Dragon Riders. "There are four other pups as well, but two of them are in New Imperium right now, and the other two are…are missing. We're still looking for them, though."

All the Dragon Riders just stared at the team in confusion. "It's okay if you don't get all the names straight the first time around." Twinkle stated. "We know, it's a big team. Of course it might take some time for people to put faces to our names."

"So you said that some black dragon took off with your friend, Lloyd?"

"Sí, he did." Tracker exclaimed.

"And now we don't know where Lloyd is." Sweetie added.

"But that couldn't be Toothless—he can't fly on his own." Hiccup reasoned.

"Was this what Toothless was using to fly?" Rocky asked, pulling over the prosthetic tail fin. Hiccup gasped in recognition as he saw it. "Yes, it is! But if Toothless was here, then how did he fly away?"

"Funny story." Kaida answered. "Somehow Lloyd's elemental power of energy gave your dragon a tail fin made of pure Elemental Energy. Maybe you could call it a Power Tail?"

"So now Toothless can fly on his own?" Astrid reasoned.

"Which means that he really could have been the one to carry off Lloyd!" Hiccup finished.

"Exactly!" Andrew exclaimed. "Which means both of them are in grave danger. The enemies that we thought weren't a threat anymore have just returned."

"What enemies?" Hiccup asked worriedly.

"The Claws of Imperium." Kelly replied bitterly. "They hunt down dragons and drain them of their powers. They…they took my parents just a few years before the Merge." With this final statement, Kelly's face fell, and silent tears slipped down her cheeks.

"So these Claws of Imperium are dragon hunters?" Cassie asked.

"Worse. They're dragon killers." Kito answered.

"A dragon cannot survive without its power. If it loses too much, then…" Kijo's voice trailed off, and Hiccup realized what he was not saying—draining all of a dragon's power would kill it.

"So if these Claws of Imperium find Toothless, then…he could die?" Hiccup reasoned.

"Yes, and Lloyd too. Once the Claws locate their target, they will not stop until they have it in their grasp." Twinkle stated.

"Well, what are we waiting for? Let's go find our friends!" Cassie blurted out.

"I agree," Kai said, "but we first need a plan. We don't know where Toothless could have taken Lloyd, so we need to be able to cover as much ground as we can."

"And neither of our teams will be able to do this alone." Zane added matter-of-factly.

"So what do you say, Dragon Riders?" Twinkle asked. "Want to go on an adventure with the Ninja and Ninja Pups?"

"What do you think, gang?" Hiccup asked, turning to the other Riders.

"I'm with him—who else?!" Tuffnut cried out, raising his fists high into the air.

"Guess I'm coming too. Somebody needs to keep this team from doin' something stupid." Ruffnut replied.

"I love this plan! Count me in!" Snoutlout exclaimed.

"Let's go do something crazy." Astrid said.

"I thought you'd never ask!" Cassie cheered.

"Um, are you sure that there isn't another option?" Fishlegs asked timidly.

"Come on, Fishlegs. It'll be fun!" Cassie assured.

"Okay, if you say so." Fishlegs replied, not really sounding like he was relieved at all.

At that, the pups barked and howled with joy. The ninja cheered and high-fived each other. Kijo beamed with excitement. The Dragon Riders, the Ninja, and the Ninja Pups were ready to ninja-GO!

Meanwhile, in a secret lab underneath Imperium, another plan was readily being hatched. "Jordana, is that scan of the scale sample you collected complete?" Ras inquired.

"Almost done, and…there! And we have a match! The dragon who flew off with the Green Ninja is definitely a Night Fury."

"A Night Fury…" Ras repeated to himself, relishing the words. "A Night Fury. Did you see which way it went?"

"From what I could see, it was headed southwest. And that green-energy-tail-thing won't last for long if my hunch is correct."

"Meaning it will have to land sooner or later. And when it does, we will track it down—and take it as our own. My master will be most pleased." Ras chuckled menacingly to himself. Those Ninja and their pesky pups would never know what hit them. And by the time they figured his plan out, it would be too late. Once the Claws of Imperium had the Night Fury, there would be nothing to stand in their way of controlling all the Merged Realms.