A week had passed since Karina had been injured. Her wing was still healing and she couldn't fly, but she had no trouble walking. She had learned our names and was eager to learn more about the ninja clan. She asked us questions and we did our best to answer them.

Karina was different from other girls. She was curious and always eager to learn more. As time passed, our friendship grew stronger. Kai, Karina, and I became close friends.

My master didn't want to send Karina away until her wing had fully healed. He was happy to see that we were getting along so well. And besides, not just anyone could go to the place where the winged ones lived. You either had to be able to fly or have permission from one of their leaders.

Sooner or later, someone would come looking for Karina. Or she would leave once her wing had healed. In the meantime, we spent most of our days training together. And when our training was done, the three of us would hang out and do all sorts of things.

But what we enjoyed most was trying out Karina's inventions. Every day she would surprise us with something new. Her inventions weren't always big or grand, but they were clever and impressive nonetheless.

While we were doing our training, my master was letting Karina use the materials around to make inventions so that she wouldn't get bored.

One day, we set out for the forest to test one of Karina's latest inventions. She was more excited and impatient than usual, and we were both curious to see what she had come up with. As we walked, Kai couldn't contain his curiosity any longer.

"Karina," he said, "I'm dying to know. What does this machine do?"

Karina was determined to keep the surprise a secret. "It's not a machine," she said. "And you'll see what it does soon enough."

"I hope it's not like last time," Kai grumbled. "It took me two weeks to get that thorn out of my arm."

"It won't be like that," Karina promised. "I promise."

"So what does it do?" Kai persisted.

"I found some ninja powder at your place," Karina explained. "I mixed it with a few other things and created a colorful explosion."

"A colorful explosion?" Kai said, looking at me in confusion. "Shou, do you understand any of this?"

I wasn't sure if I understood either, but we had another problem to worry about. "I don't know," I said. "But we'd better hurry up before it gets dark or the master will scold us again."

Just then, Karina called out excitedly. "This is the place!" she said. "We can set it off here."

We arrived at a clearing on a high plateau. There weren't many trees around and the area was calm and peaceful. From our vantage point, we could see the entire ninja clan village below us.

Karina set up her invention and lit the fuse. "Stand back," she warned us. "Here it comes."

The fuse burned down but nothing happened. Kai looked disappointed. "What, that's it?" he said.

"It wasn't supposed to be like that," Karina said, frowning.

Just when we thought the experiment had failed, Karina's invention suddenly sprang to life. I grabbed Kai and Karina and pulled them back to a safe distance. The invention shot up into the sky at an incredible speed. When it reached its peak, it exploded in a shower of colorful sparks.

It was a beautiful sight. The entire village was bathed in bright, colorful light. Kai was amazed. "Wow," he said. "What do you call that thing you made?"

"I never really thought about it," Karina admitted. "But it might have something to do with the weather."

I spoke up, offering the first name that came to mind. "Fireworks," I said.

Karina's face lit up with a smile. "That's a great name for it," she said. "Fireworks."

We packed up our things and headed back home. Every day was filled with joy and laughter, but nothing lasts forever. When we arrived back at the village, there was another winged man waiting for us. He was older than my master but still tall and imposing. It was Karina's grandfather.

He told us that he had been searching for Karina ever since she disappeared and that he had missed her terribly. I knew then that it was time to say goodbye.

Karina hugged us tightly before she left and gave us some fireworks as a parting gift. I didn't want those days to end, but there was nothing I could do to stop time from moving forward.

Karina's wing had healed enough for her to fly back home with her grandfather. I could see the excitement in her eyes as she prepared to leave. I wished that she could stay a little longer, but I knew it would be rude to ask.

After she left, we felt her absence keenly. There were no more inventions or surprises. It was just Kai and me.

Our master could see that we were sad to see Karina go. He offered us some words of comfort and wisdom.

"It's good to wait if the one you're waiting for will return," he said. "And it's good to miss someone if they miss you too. Don't worry. I'm sure Karina will come to visit us once in a while."

My master was right. Kai didn't seem to care one way or the other, but I found comfort in my master's words.

I didn't know how long it would be before Karina came back to visit us, but I wasn't going to sit around and wait. Kai and I continued our training, working hard to become skilled ninjas.

But something had changed. It was subtle at first, but I couldn't shake the feeling that Kai was different. He seemed to be growing more distant and aloof.

And I wasn't the only one who noticed the change in him.