The Underworld had taken some time for Zane to get used to, but now the dim light and gaping caverns didn't seem so strange to him anymore. Either way, it was home now, and he couldn't complain. There was still so much about this place he didn't understand, and maybe he never would.

But he didn't think he'd ever get used to the creatures that lived there, though. Skeletal beings that seemed to be more brawn than brain, harmless, as Wu had reassured him. And indeed, they weren't half as menacing as they had seemed when Zane and his friends had first stumbled upon them as children. It didn't take long for Zane to realize that Wu held some sort of authority over them. When he asked about this, Wu simply stated that he had won their loyalty shortly after being banished here. Zane mostly tried to stay out of their way and kept to himself.

One perk to living here was that Zane got a lot more one-on-one training with Wu. His brothers envied him for the extra attention. But there wasn't much else for him to do, and Wu insisted that he keep up a regimen to keep from becoming idle. Wu was more strict in the extra hours, but this didn't bother Zane He appreciated that his teacher expected only the best from him.

However, there were many occasions when Wu would disappear for long periods of time. Recently, he'd been doing this during training sessions as well. There were days when he would be late or show up for only a few brief moments. Zane wondered where he could possibly be going if he was banished.

"My physical body is trapped here," Wu had explained. "But I can visit Ninjago as an intangible observer, a shadow, if you will. You may not have realized that was my form on the day we first met. When I leave here, I go to find my brother. I have told you how dangerous he is. Now he has hidden the weapons, and I must find them and take them back, before he uses them for evil."

"And what if he does?" Zane asked. "How can you stop him?"

But Wu had shaken his head. "That's not for you to worry about. Not yet."

. . . 

Though it had been a long time since their first meeting with Wu, the boys had not forgotten his impressive display of Spinjitzu. Wu made sure of that. He would use it occasionally during practice fights, just to remind them of their ultimate goal. And after years of begging, years of honing their skills in all other aspects of their training, Wu had finally agreed to begin teaching them Spinjitzu.

The problem was, it wasn't as clear cut as the other moves they had studied so far. Master Wu had constructed a course for them and had them practicing on it daily, promising that it would soon help them unlock the power that they each sought. To them, it didn't seem much like of method to forming a colorful tornado of "butt-kicking awesomeness," but they had learned by now not to question their teacher's instructions. Well, not directly at least.

"When are we going to learn some actual Spinjitzu?" Jay whined in the absence of their Sensei. "I'm so sick of this obstacle course. I could do it backwards if I wanted!"

"I'm sure that Sensei Wu would not have us do anything that did not serve a specific purpose," Zane said, trying to sound more confident than he felt. He trusted Sensei Wu as a teacher, but he couldn't justify this exercise with what they had seen. Still, he knew that there had to be some purpose to the course. "If we keep practicing, I truly believe that we will achieve something worthwhile."

Cole glanced at the door as if he expected their teacher to return at any moment and hear them complaining. "Zane's right. Just because we don't understand the point of it doesn't mean that there isn't one."

"Can we at least take a break?" Kai asked.

Cole thought about it briefly and nodded. "Sure. A break would be nice right about now."

Not a moment later, the door burst open and their sensei entered. Zane hurriedly lined up alongside the others in front of Wu. Zane couldn't help but notice, as he often did, how quickly they'd all grown recently. Naturally, their heights fluctuated over time, but collectively they could more or less meet Wu's gaze now, and likely some of them would still continue to grow.

"It's time to show me what you've learned," Wu stated, and Zane noticed his brothers exchanging nervous glances. Zane had to admit that he, also, was confused. They had not learned anything yet, surely he knew that?

A group of skeletal soldiers was filing in after Wu – for a while now, Sensei had been pitting the boys against the Skulkin to let them practice against new opponents and perform as a whole team. Like Zane, the others found them a lot less intimidating once they'd overpowered them a few times.

"Whoa, hang on a minute!" Cole objected. "Honestly, Sensei, We still haven't figured out Spinjitzu."

"Spinjiztu is already inside each and every one of you," he said sternly. "But it will only be unlocked when the key is ready to be found."

Zane pondered this riddle while Wu made his way to his seat at the front of the room. Their sensei began making himself a pot of tea while the horde of Skulkin surrounded his students. His meaning hadn't been very clear, but then again, he usually wasn't. Unsure of themselves, Zane, Jay, Cole, and Kai had no choice but to prepare themselves for a fight.

"Come on boys, let's show 'em what we got," Cole said under his breath, though Zane suspected that he, too, was not as confident as he pretended.

The Skulkin were the first to make a move, surging forward like an ocean tide and nearly overwhelming the ninja. Typically, they weren't all that difficult to defeat, the main issue was that they wouldn't stay down. They were undead, after all, and even if you knocked off a head or an arm, they would simply put themselves back together and come back for more.

Even though the boys were each giving it their best effort, not wanting to let Sensei Wu down, Zane feared that it wouldn't be enough. This resembled any other sparring match, yet the pressure to do well made him more nervous than he would normally be. He simply couldn't imagine how they were meant to achieve Spinjitzu. Zane tried to focus on what Sensei Wu had said about a key. He was always using metaphors like that to teach them. The answer must be hiding in plain sight.

Zane was snapped out of his thoughts when he heard an exclamation from Jay.

"Guys, look!" he was saying. "It's just like the training course!" Zane kicked away another skeleton and paused to glance at Jay as he fell into the routine they'd knew so well. He skipped over the heads of a couple of skeletons, then flipped over a few swinging swords.

"Over the planks," he said, listing off the familiar movements. "Dodge the swords . . . and here comes the dummy – ka ching!" In the final move he spun around and whacked a skeleton away with his nunchucks as blue sparks began to flash around him. In an instant he was hidden from view by a whirling blue tornado crackling energy. "Wahooo!"

Zane marveled as, all around him the skeleton army was effortlessly knocked away by the power of his cyclone. He spun around the cavern, picking them off one by one.

"Spinjitzu!" Kai exclaimed. "Jay! What's the key?"

"I'm just going through the motions," Jay explained. "This is what Sensei must have meant when he said we already know it!"

Of course! Zane immediately copied Jay, imagining that course was in front of him. When he spun around he found himself engulfed in shards of ice. The world seemed to be moving in slow motion, and now the Skulkin were no match, much too slow to react to his attacks.

He batted away one after the other, then easily came to a stop before a couple of skeletons who had been too distracted insulting one another. "I sense you do not stand a chance," he quipped, smirking as the ran away in fear.

"Retreat!" Samukai, their general, called as all four of the newest Spinjitzu Masters sent them running from the room. The boys halted to watch their enemy flee out the door.

"Ha! Guess they didn't want a second serving of these babies," Cole gloated as he flexed. "Good thing they didn't check out the merchandise in the back!" He turned and flinched when he saw that their master was still observing from atop his throne. In all the excitement, they had forgotten he was there. He quickly put his arms down and nudged his brothers to turn as well, and they all kneeled before their sensei.

Wu slowly set down his teacup. "Don't get ahead of yourselves. That was a poor performance, even for a first attempt. Still, I suppose that this is the moment you've been training for since the day you first came. Perhaps you do deserve to celebrate."

"Thank you, Sensei," Cole said solemnly. "We wouldn't have gotten this far without you."

Wu nodded. "And you still have a long way to go yet. Do not think that your training ends here – you have barely scratched the surface of what you are truly capable of." With that, he rose to his feet and left them to rejoice.

Jay leapt to his feet. "Woohoo! Did you see that? I was amazing!"

"Uh, did you see me? I was spectacular!" Kai argued

"Hey, I'm the one who figure it out first!"

"But I believe I had the better form," Zane cut in.

"Ha, you wish!" Cole said, rolling his eyes. "I knew that course better than any of you, clearly I was the best!"

"The best at tripping over yourself," Kai teased him.

Zane chuckled to himself as his brothers went back and forth, and it occurred to him how happy he was since coming here. He was proud of himself, proud of all of them, for putting in all the hard work to be able to achieve their goal and pull off something they'd been dreaming of for years. He had no regrets, choosing them as his family. Even if no one else wanted him, they did. It felt good to be a part of something, to be able to participate and laugh and truly enjoy himself without feeling singled out. They were a team, and this victory they shared as one.