((AN: In case it wasn't previously clear, do not follow Amy's lead when you think a friend of yours has a head injury, especially if they start behaving abnormally or seems confused. Take them to a doctor first. You all have good sense about these things, right?

Content warnings for this chapter: Silver's part has vomiting, more explicit mentions of parasites, and some minor body horror. Nothing I can think of in Sonic and Shadow's part.))

Silver dragged his fingers on the surface of the cafe table. Amy was insistent on eating here because the hospital was within walking distance, and he didn't refuse. The hospital was fine, he said, but not the Doctor - Amy couldn't see why he was scared of one but not the other, but the truth was that the concepts weren't linked together in his mind. A Doctor was controlling, not understanding, cruel. A hospital was… some kind of place. Maybe. He couldn't quite remember, but he'd figure it out eventually.

Food was a strange experience. He didn't pick the food he was given himself - Amy chose everything, telling him to just drink water and relax. A woman brought it out to him on top of a white plate, along with pieces of metal wrapped in a napkin. He looked at it - a bed of green leaves with some red slivers and blue spheres - until he realized Amy wouldn't be satisfied unless he did something with it. Following her lead, he took one of the metal pieces and stabbed one of the slivers before putting it inside of his mouth. It felt like sparks inside of his mouth, and his eyes went wide at the sensation of it. He recognized before how to feel, see, smell, and hear, but now he remembered what taste was like, and he wanted to know more. Eating by itself seemed simple enough, since he just had to take the object in front of him, chew, and swallow. He felt better after doing it, and Amy at least seemed to be under the impression that it was necessary. The complexity of experiencing tastes, though, is what made him curious. The red thing was spicy, he recalled the word, but the green things were bitter, the purple spheres were sweet, and the white liquid tasted like nothing at all. He experimented, eating slowly, then quickly, then combining the objects when he put them in his mouth. All this took a long time, and that was fine by him as well. Each bite, though different, felt good.

He almost forgot about Amy, who ate across the table from him. The woman had brought her some other kind of food, but since she had already finished eating she occupied herself with spinning her fork on her now empty plate. She watched him, her lips pressed together in a thin line, before tilting her head to the side and sighing. "Silver, are you sure you're okay? You're acting really weird."

He stopped mid bite. "Weird how?" he asked, his mouth still full and his teeth clattering against the fork.

"I don't know, you're not talking, you're walking funny… and you just ate that blueberry with a chile. I thought you didn't like spicy food."

He swallowed, then mirrored Amy's head tilt. "This is the food you gave me. You told me to eat, so I am eating."

"Well, yeah, but I didn't know it had peppers in it…I figured that a salad was a safe choice because you would probably like it."

"Are other foods dangerous?"

Amy giggled to herself. "You're so funny, Silver."

Silver didn't know what was funny about it. He thought it was a fair question. He kept the fork in his mouth by itself, feeling the cool metal against his tongue.

His stomach rumbled again, but it felt different from before. This wasn't like earlier, when he was hungry - the feeling wasn't Pain or emptiness, but rather, too much sensation all at once. Silver doubled over. His blood felt thicker, and it itched under his skin, scratching him from the inside out. His stomach folded and pressed on itself, and he felt the pressure of something coming up his throat. Caught off guard, his body wobbled and his vision spun. He put his hands down on the table in an effort to keep balance, but it was unsuccessful; instead, he stumbled heavily to the side, feeling like his legs were moving on their own, and his chest heaved with heavy panting. The table toppled, dishes flying and breaking against the ground with their half eaten food strewn everywhere, and the metal pieces skittered across the ground. His heart pounded, his breathing more frantic and urgent than ever. Did he eat something dangerous, or was this something else? It was overwhelming. He could barely think, so he let himself follow his first impulse; on instinct alone, he began to run.

"Silver, wait!" Amy yelled out after him, but he did not slow. He didn't know where he was going; he just pushed past people, one hand on his stomach and the other on his mouth. She lagged behind him, handing some kind of slips to the Waiter, and there was a throng of people between the two of them when he lost sight of her. He made his movements predictable; she needed to stay close, he thought, but the Pain came back to his head and it was too much, too much, too much.

He tucked into a dark alley before finally falling down. His knees and elbows got skinned on the gravel, but he only briefly noted it before his attention was called back to the inside of his body. He closed his eyes and curled up, shivering violently. He realized he was still holding on to the fork, and without thinking, he put it back in his mouth. Finally, he felt something solidify in his stomach, then slowly bubble up his throat. It rose up to meet the fork, and he felt the metal dissolve and disperse. With a heave, he opened his mouth and let the bile spill out. What came out was some half digested food as he expected, but there was something else too. It was black and shining….and beautiful. Something in the back of his mind remembered that this looked what was on the robot in the woods, but while before it had scared him, now it felt familiar. Like…a pet? Definitely not. A friend? Maybe, that's a little closer. It felt just as much a part of him as his arm or his chest, but it wasn't quite him, either. The pressure in his body diminished some, but he felt a small twinge of Pain against his skull. He could feel something snaking around inside, but he wasn't concerned about that. Instead, he felt worried for the black mass that came out of him. It couldn't survive outside like this, he realized. He had to find a host for it, and quickly, or it wouldn't survive.

Amy rounded the corner, her face turned red and her chest heaving with the effort of pronounced breathing. She glanced around the alley before her eyes landed on him, and she began to approach. "Silver! What on– I knew we should have gone to the hospital first! You can't even keep food down! You need to come with me right now!"

The thing writhed in his hands at the approach of the other hedgehog, and he turned his head to look at her. He put his hands down, coaxing it into his grasp, and it moved into his arms in a rippling motion. Standing up, he let it wrap around his arm like a serpent before gathering in a pool in his palms.

"Why are you– ugh, gross! Silver, get rid of that thing! You don't even know what that is!"

A glazed expression came on Silver's face, and he broke into a small smile as the calm spread out from his mind. He could feel the pulsing in his skull, the imposed warmth it was giving him. It was so obvious now, he realized. How could he have not seen it before? How important it was?

His hands moved with a speed unknown to him before, launching the substance towards Amy. It landed in a splatter across her neck and chest, allowing the impact to settle before it began to crawl across her skin. She let out a high pitched scream as she tried scraping the goop off of her, but Silver's calm didn't waver in the slightest. If anything, he felt more at ease as he watched it stretch upward. It climbed up her body like the roots of the world's most wonderful plant, and Silver's eyes went half lidded in contentment as it entered her throat, her ears, her eyes. He sighed as her screaming stopped, blocked by the black entering her throat, and he grabbed her as she collapsed in a comforting embrace. He was just so Happy. Soon, she would know about it too. The bliss of the Purpose. He couldn't wait.

Every jolt and buckle of the plane's flight made Sonic wince. As it turns out, Tails had made several changes to the controls; he couldn't maneuver the way he wanted to, instead hitting bumps and drafts hard. A small part of him wanted to lecture the kid about making too many changes without telling him what they were, since it was still technically Sonic's plane, but then he thought the better of it. After all, until today, he hadn't actually flown it himself in… how long had it been? Two years? Three? He let himself have an embarrassed laugh to himself. Okay, maybe going on a mode of transportation that was especially affected by turbulence was not the smartest idea, and maybe he was a little rusty at the actual flying part, but it's not like he had any other options. Well, one other option. But like hell he was going to stay home.

In any case, he had made it to the base, and some poor low-level private had let him in on sight. He knew he wouldn't be that lucky forever, and had to think of a different way to get past the GUN personnel who would know better than to let him go anywhere.

So here he was, army crawling through an air duct.

It was hell on his arms. His legs were usually where most of his power came from - all those years of running gave them muscles of steel - but with only one of them at full power and the other surrounded by solid plaster, they couldn't do much of anything. His elbows were already raw from rubbing against the metal, and the heat of it made him feel uncomfortable. Each drag against the surface felt startling, with small bumps sending jolts of pain up his leg. Before long, though, he heard two familiar voices that made it all worth it.

"Commander," Rouge was saying from… somewhere beneath him. His right? He moved in that direction, trying not to make a sound. "Why is this any different from the times Doctor Eggman has disappeared from our radar before? Normally this kind of thing is a standard alert, and he shows up on his own eventually."

"…Whether we like it or not," came a mumble from Shadow.

The Commander's voice, in contrast to those two, was loud and devoid of any obvious emotion. It echoed through the air duct, sound practically ricocheting around the sides, and dust filled the air. "Normally, we would be in agreement with you. The man is labelled as a terrorist, but aside from some minor property damage, the last attack deliberately attributed to him was the destruction of the side of the moon three years ago. Nothing particularly pressing or concerning."

"Not shattering the planet? Or the intergalactic slave trade?" Rouge piped in. Sonic could tell that some incredulousness was seeping in her voice, but she was trying hard to hold it back - she was in the presence of someone important, and even for Rouge, sometimes it was better to tone it down.

"Unproven that he is the cause, and outside our jurisdiction," the Commander replied. "In any case, he is normally lower priority than our other pressing public safety concerns. However, we received this transmission four days ago that makes us believe that he is devising some kind of new weapon - one that could be disastrous if left unchecked."

Some light shone through one of the grates, and Sonic moved closer. He was directly overtop of them now; he could see the three of them, facing the screen as the Commander queued up the transmission. From here, Shadow and Rouge seemed so small - the Commander imposed his status through physical stature and extraordinary arrogance, even for a human. Still, they both held themselves confidently, standing up straight and looking him in the eye. It must mean something that they could call out and question someone so high up in rank; Sonic realized he didn't know how exactly Shadow worked for GUN, other than that he was some kind of agent, but he had no doubt that his presence was well known. There were so many things he didn't know about Shadow, he realized. And yeah, the hedgehog was more than a little introverted, but maybe some of that was because Sonic never bothered to ask the right questions. When he saw him, he usually was contented with the challenge of a race, or exchanging jabs, or the occasionally fruitful efforts to get at Shadow's elusive smile….

The screen filled with static, the sound startling Sonic enough to almost jump. One of Eggman's assistant robots filled the screen, shooting selfie style. The robots weren't meant to display emotion, but Eggman regularly slipped in that regard; this one (was this Orbot? He thought that was right) looked worried, fidgeting with the recording device and blinking his eye sensors.

"Hello? Hello, is this on? Are you there? Oh my, I'm going to get dissembled for this for sure."

"What are you doing over there?"

"Just…tuning up my circuits, sir! Preparing for the big day!"

"Well, good! Come back here when you are done."

The robot turned back the camera, his "voice" lower. "Guardian Unit of Nations, I am reporting this to you against my programming and my instructions because this is a dire situation. The Doctor is doing something new. I don't know how to describe it…he's been researching infectious diseases and viruses, and he hasn't slept in three days."

Some clatters came in the background as Eggman screeched at whatever his latest project was in frustration. Smaller robots whirred around in the background, carrying wrenches and building materials. Orbot brought the camera closer to himself, as if to try and hide it.

"The Doctor is…erratic, at best. At least before, what he's done has been targeted. He'd maybe blow up a building, or hold someone ransom. I think this time, though, he's messing with something really dangerous. I think he's about to unleash a bioweapon, and as usual, he isn't thinking things through."

"Ah, yes, I've done it! Orbot, come over hear and take a look at the future, model H.E.L.– wait, no, what are you–"

There was a sound of crunching metal, and the video returned to static. After a second or two, Shadow tiled his head down and crossed his arms. "That's the whole transmission?"

The Commander nodded.

"So he's got another project? Why is this so concerning?"

"If this transmission is correct, Project, then the Doctor could be manufacturing the next plague. As it is, we'll be lucky if he hasn't already unleashed it, either on purpose or by accident. Your top priority is to find him and take him in, alive, for questioning. Understood?"

"Yes, sir," Rouge replied.

Shadow said nothing, staring off to the side. His contempt for the Commander was obvious, and Sonic could guess he knew why; from everything he had been told, he wasn't a big fan of the man either.

"Then get to it. I'll leave you here to gather as much information from the transmission as you can, then track down your most promising leads. I expect a status report every three hours."

"Understood."

The Commander left the room. Shadow and Rouge stood in silence for a minute, playing the transmission a few more times, before Shadow quickly turned around. Pointing his hands at the vent, he shouted with force, "Chaos Spear!" Electric energy shot out from the tips of his fingers towards the vent, and Sonic yelped involuntarily as he narrowly dodged the blades of Chaos. As he calmed down from the initial attack, he looked through the new smoldering holes in the vent - only to find Shadow staring right at him.

"What are you doing here!?" Shadow yelled. "I told you to stay home and rest!"

Sonic snorted. "Resting is boring! I figured I could help you with your secret mission-thingy."

"You thought wrong. Leave, now!"

Rouge turned to him and grabbed his arm. His head whipped around to see her, and she took on the tone of a concerned friend. "Shadow, maybe he's right. I'm sure the Commander would let him help us."

He sniffed. "The Commander will take advantage of anyone with a pulse if you let him. Sonic is injured. He is in no condition to take on anything right now."

"He got himself here fine, didn't he? Besides, he seems willing to help out. If it's only information gathering, we can always take him home before the real fight."

"…he would just slow me down."

"When has Sonic ever slowed anything down?"

Sonic listened to the bickering, the heat of the vent slowly getting to him. "Please, guys. I came all this way. If I'm not helpful, you can send me home and I'll understand, but if Egghead's really up to something dangerous then you know there's nobody more qualified than me to crack him!"

It was hard to be convincing when he literally could not move. Rouge looked at him with pity, leaning against the wall and giving Shadow a look that practically said 'just throw the kid a damn bone.' Shadow stopped, rewinding the transmission and pausing at the part that showed the most background behind the bot. "Do you recognize this place at all? From this image."

Sonic stopped and squinted. "Most of Eggman's bases look pretty simil– wait! Can your GUN computers zoom in on that thing in the upper right corner?"

Shadow hit a few buttons, and the corner got bigger. As the image clarified itself, Sonic sighed with relief.

"That bot, there, holding the bolts. It's a support bot that he used to use four years ago, but deactivated most of them after a few weeks when I, er, crushed their weak spots enough times."

"So they're old bots. How is that helpful?"

"Because if he's using it again, that probably means he went back to his old base where he made that model. He wouldn't transport it anywhere cause that's a waste of resources, but if he thinks nobody knows where he is and it's just going to sit there anyway–"

"–Then he'd reactivate it so that he could have another set of hands. That's…actually smart."

"I'm sorry," Sonic jeered, "I didn't hear that – what did you just say?"

Shadow scoffed. Crossing his arms, he turned back to look at Sonic and ignored his smug grin. "And which base would this be? You aren't saying the most important part."

Sonic brought his hand to his chin, mock scratching it. Shadow rolled his eyes, but Rouge grinned, used to his antics. "Well, lemme think. Four years ago was before the moon incident, but after the Chaos incident…that must've been when he was experimenting with the whole government hacking thing. He got a base on an island in the middle of the ocean, since it was technically international waters and could get away with more stuff there. And if he's really making a bioweapon, that's a good way to make sure that it doesn't get make people sick before, ya know, it's supposed to."

Rouge laughed. "Never thought I'd hear you use a phrase like 'international waters,' Sonic."

He grinned. "I've been fighting the Doc for a long time. Gotta know this stuff." He turned his gaze to Shadow, who was looking directly at him. Sonic could feel himself sweat…but that must just be from the heat from the vent. Right?

"Do you know the coordinates?" he said.

"Yeah, I'll put them down once I'm out of here. So can I help you or not?"

Shadow looked at Rouge, then the transmission, then Sonic. His arms uncrossed, and he closed his eyes. "The second, and I do mean the second, that you slow me down or interfere with me in any way, you will get much worse than a broken leg. Got it?"

Sonic's heart leapt in his chest, and he broke out in a big smile. He did it! "Yeah, let's do this! Well, after one thing."

"And what would that be, you pest?"

"Er, I'm kind of stuck in the vent. Can you help me out?"