"The train for Station Square will be departing soon..."

"No! Wait!" Rouge came barreling down the path left by earlier explorers into the jungle. Thanks to some quick directions given to her by Prof. Kagaku and Talula, exiting the jungle was much easier than she'd expected.

Catching the train, however, was a different matter...

"Wait for me!" Rouge flew up to the train station, skipping the steps altogether, and arrived at the door...

...just in time to see the train start to leave.

"Oh, no you don't!" Rouge took a running start, then barely managed to grab the back door of the train.

Opening it, jumping inside, and slamming it quickly, the exhausted bat slumped into a chair, glaring at the people who stared at her.

'Station Square, here I come...'

~*~

"Oh, where have you gotten to, Sonic?" Amy half-wailed, staring out the apartment window.

"Please, Amy, Sonic's only been gone one day. Give him some time, he'll be back," Tails pleaded with the distraught girl. "He just went out to look for Shadow. Maybe he found something."

"...Sonic," Amy sighed, looking past her reflection out onto the busy street.

"To tell the truth... it's really not Sonic I'm worried about," Tails said slowly. "It's... Shadow. I mean, Sonic's pretty smart about how to act in the city, you know, but Shadow... I mean, Shadow's lived up in space all his life. He probably doesn't know what life is like on Earth at all."

Amy sighed. "I know. I'm being selfish. Sonic can take care of himself." Her voice started to quaver. "I... I should know that... He's saved me so many times, I've never really thought about how much he lived by himself before he met me... us...

"But even so, that doesn't stop me from worrying about him..."

"Amy..." Tails watched Amy as she looked out of the window. "He'll be back. You'll see. He always comes back. And he'll bring Shadow with him."

"That's right..." Amy stood up. "I suppose I should stop pouting... I want to look good for the boys when they get back." Amy turned and walked to the bathroom to freshen up.

Tails smiled.

'I know how much you're worrying, Amy, even if you won't let on... You care about him a lot. Both of them.

'But he'll be back... he always manages to return from everywhere he goes, safe and sound.'

Tails frowned. 'But it is really Shadow I'm worried about. Since G.U.N.'s come back, who knows what's going to happen? Why are they still after him?'

~*~

At around lunchtime that day, there was a knock at Amy's door.

Upon answering it, Amy found herself face-to-face with none other than Rouge.

"I'm here to see Tails. Where is he?"

After sitting down, Rouge gave a brief summary of what she had found since G.U.N. had attacked Sonic and Shadow at Emerald Coast to Amy and Tails.

"...and then Sonic told me to come here, to tell you to get to South Island. He said you'd know what to do."

Before Tails could respond, Amy had jumped up furiously. "That jerk! What could he be thinking?!"

But Tails was looking at the situation in a different light. Grinning, he started to laugh. Rouge and Amy stared at Tails as if he had gone insane.

"What's so funny?" Amy asked, irritated.

"Sonic!" Tails blurted out. "Wow, I completely underestimated him. I'd never expect someone like him to plan ahead like that!"

"What?!" both girls yelled impatiently.

Tails calmed down enough to explain. "Amy, do you remember how Sonic and I got into a fight, back on South Island?"

Amy thought back. "Yeah, it was over some kind of machine that you'd... built..." Her face slowly started to break into a smile.

Rouge was clueless. "What in the world are you two talking about?"

However, Tails was hurriedly explaining the rest to Amy. "Since Sonic's with G.U.N. now, if we can track down Sonic, we can--"

"--find G.U.N. too!" Amy finished. "Then we can shut them down for good!"

"Hey, Rouge, do you want to come along?" Tails asked the bewildered spy.

"Um... sure, if you'll explain to me what's going on."

"I'll do that on the way there. In the meantime, let's go grab the Tornado!"

As the three rushed out of the apartment building, Amy asked, "Where have you been keeping the Tornado, anyway?"

Tails grinned. "I've been keeping it in a shed, downtown. Being a town hero has its perks, you know."

"Town hero?" Rouge repeated.

"It's a very, very long story... to make it short, Eggman fired a missile on the city, but it was a dud. Basically, I beat him to it before he could detonate it, then I cut the wires. No big deal."

"Wow. I'm impressed," Rouge said, raising an eyebrow. "Given some time, you could probably be an even better scientist than that mad doctor." Tails blushed.

"Thanks..."

~*~

As the plane veered south over the ocean, Tails took the time to fill Rouge in on what was going on.

"See, a long time ago, Sonic and I used to live on South Island."

"I know that much. Knuckles told me."

"Anyway, one day, Eggman came to us, tricked us into going to his lab. But to show us how to get there, he gave us this wristwatch navigator. When we got to his place, he scanned Sonic and put his life data into a robot named Metal Sonic."

"Hmph," Amy sniffed. "I remember that thing."

"After that, Amy," Tails sighed. Continuing, he explained, "I won't go into much detail about Metal, since that's not important right now. But what I did was I rewired the navigator to pick up Metal and Sonic's brainwaves, kind of like a way to track them down."

"So, if you can pick up Sonic's brainwaves," Rouge said, "then we can find G.U.N. at the same time!"

"Right," Tails said. "And, if you two ladies will give me a few minutes once we get there, I'm pretty sure I can set it up on my computer to make it just a little bit easier than that..."

A thought went through Rouge's mind at that moment. "Tails?" she asked. "If you could pick up Sonic's location... do you think it'd be possible to get Shadow's, too?"

Tails shook his head. "No... 'fraid not. I don't have a trace on Shadow's brainwaves or anything--"

Rouge stopped Tails. "No, listen to me. You created a false Chaos Emerald once, didn't you?"

Tails blinked. "Yeah. How'd you know about--"

"Never mind how I know. The thing is, you must know something about the energy patterns of the Chaos Emeralds, right?"

"Right."

"Now, if you can set up your navigator to track an energy pattern like that of a Chaos Emerald, you'll be able to find Shadow. Trust me."

"You're sure?" Tails was skeptical. "Is he carrying an Emerald around with him, or--"

"No. I've been doing some research, and, well, I have a feeling that Shadow has the power of the Chaos Emeralds within himself. Maybe even the same with Sonic."

Tails gawked. "You're kidding me."

Rouge shook her head. "No, I'm not. When I was still working as a spy, I had to find information on Project: Shadow. Chaos Energy was a large part of that project. I'm not 100% positive, but I'm pretty sure that Shadow and the Chaos Emeralds are somehow linked together." She looked at Tails. "Do you know the concept of chi?"

"You mean, like, the energy that flows in all living things?"

"Yeah. I've been talking to Knuckles, and he knows about stuff like that. According to him and Tikal, every time someone comes into contact with a Chaos Emerald, a little bit of the Emerald's power becomes fused with that person's chi. Just a little bit.

"The thing is, we wonder if Shadow's chi is completely made up of Chaos Energy, as if that's what he lives on."

Tails bit his lip. "But, if that's so... Chaos Energy never changes form. It just keeps on going. If that's so with Shadow, then..."

"That's the whole point," Rouge sighed. "Project: Shadow wasn't just looking for the Ultimate Life Form. It was a quest...

"...to find immortality."

Amy gasped. Rouge continued. "Did you see how quickly Shadow healed from his burns after falling from space? And how quickly his fur grew back? I swear... it has to be the doing of the Chaos Emeralds.

"Put plainly... Shadow can't die. He was created to live forever."

"That's... unnatural," Tails said, his voice faltering. "I knew the Chaos Emeralds had the potential to give anyone immense power, but... eternal life?"

Amy broke in. "It's... amazing. It's horrible, but it's amazing in the same way. The same Emeralds can cause terrible destruction... but endless life."

Rouge sighed. "But the Chaos Energy might become Shadow's own undoing, too. G.U.N. was trying to create a machine to drain Chaos Energy. I don't know if it'll work, though, since I freed Kagaku. But the other thing was, could the Chaos Energy be dangerous to Shadow from the inside out?"

No one spoke. The three sat in the airplane quietly.

After a few minutes, Tails broke the silence.

"All right, everyone... we're here."

~*~

Dashing inside the airplane house, Tails reached for the machine tucked away in the corner.

Amy smiled. "I'm so glad Sonic didn't make you throw it away after all."

Tails laughed. "Where would I throw it? We're out in the middle of the ocean!" The two-tailed fox started up the electricity. "Now, just give me a few seconds..." Tails opened up a laptop that he'd brought along.

"Now what are you doing?" Rouge asked, looking over Tails' shoulder.

"You ever used a GPS?"

"GP... what?" Amy asked.

"Global Positioning System. Hang on a minute..." Tails hooked up the laptop to the small wristwatch navigator.

In seconds, a map of the Earth popped up on Tails' computer. Two dots began blinking. "See," Tails explained, "this..." he pointed to one dot, "is where we are. And this," he pointed to the other one, "is where Sonic is. Looks like... somewhere in the jungle by the Mystic Ruins! Now..." Tails ran out to the Tornado and opened up a compartment, taking out a small box. "Here we go," he smiled. "The false Emerald." He turned and smiled at Rouge. "If I reverse the energy reading I get from this, it'll be the same as a regular Chaos Emerald."

Tails quickly scanned the fake Emerald, then downloaded the information. He stood up and grinned. "We're all set to go!"

When they had all gotten back into the Tornado and were headed towards the Mystic Ruins again, Rouge asked, "So... where is Shadow?"

Tails handed her the laptop. "The program's already running, so..."

Rouge opened the laptop and blinked.

"So? Where is he?" Tails asked.

"He's... he's in the jungle, too...

"He's headed right towards Sonic."

"What?" Then, that means he's headed towards G.U.N., too!" Amy yelped.

"Wait... just a minute..." Rouge looked at the map more closely. "It doesn't look like he's moving that quickly, and he's going to run across Prof. Kagaku and Talula first, so they'll probably stop him before he gets too far..."

"Prof. Kagaku? Talula? Who're they?" Tails asked.

"Oh... just some folks I met in the jungle."

The plane made a dull roaring sound as it zoomed across the ocean towards the jungles...