Disclaimer: I do not own Fusion fall, or any of the Cartoon Network characters.

A/N: Sorry it's taken so long for me to get out a new chapter. For those interested I've rewrote chapters 1 and 2. I'm slowly working on the other chapters. Thanks to Lightning Bird for betaing this chapter for me.

Rex grunted as he blocked another strike from his opponent. After having fought for over two hours straight, Rex could feel the exhaustion setting in, and knew he needed to put some breathing room between them. Dodging another hit, he tried to call on his nanites, only to remember to late how bad an idea that was. Seconds later he felt white hot pain surge through his body as his nanites went out of control. He was barely aware of the fact that he was screaming, that his limbs were trying to rapidly transform, when he felt someone come up behind him and pin his jerking arms to his sides. As he was pulled against someone's chest, his pain-filled mind slowly registered the fact that his nanites were not attacking, but he couldn't understand why not.

"Rex! I need you to calm down."

The young EVO knew that voice, could feel a name just at the edge of his clouded mind, but the answer continued to elude him.

"Rex, that's enough. You're going to be fine, just calm down."

A man's voice, a trusted voice, but who...SIX...it was Six's voice. If the older man was here than that meant he was safe, after all, Six would never let anything hurt Rex if he could help it. As if that thought was some signal that the nanites were waiting for, they began to power down, and Rex groaned in relief as the pain became the dull throb of over-used muscles and joints. Without the pain-fueled adrenaline coursing through his body, the teen's legs collapsed out from under him, and it was only the agent's grip on him that kept him from hitting the training room floor. Feeling more than hearing the sigh Six let out, he felt himself being lowered to the floor. So that he was leaning against the older man's chest, his head resting on his shoulder.

"You ok there, Chief?"

The teen slowly cracked open his eyes, and could just make out the blurry figure of his chimp friend, Bobo. Before he answered, he looked around and saw a blurry group of Providence agents nearby, so he decided not to say how he truly felt.

"I'll be fine, Bobo." Rex's voice was hoarse from screaming, and all he wanted to do was sleep, but there was something he was suppose to be doing, something important. As if reading his thoughts, Six shifted and spoke up.

"I think that's enough training for today, Rex," said Six, and Rex could just pick up the slight softening of his tone that only seemed to happen around him and Dr. Holiday.

Knowing that the green-suited agent would take care of him, the young EVO let his eyes slip shut, and his body completely relaxed against the older man's.

Six looked down as his young charge went limp, concern filling him (though you couldn't tell from his face) as the teen fell into a light doze. Looking up and casting his sharp gaze around the Providence Keep's training room, Six watched as the other agents quickly went back to their own training. All of them knew how protective the Senior agent was of Rex, and most made sure never to push the man when he was in mother hawk mode.

Once Six was sure that the others were occupying themselves, he glanced back down at Rex and gave another silent sigh. The younger man had been training hard, trying to learn to fight without the help of his nanites, but there were still times where he would forget and the results had been increasingly painful for him. They still didn't know what was causing his nanites to act up, but he knew they needed to find out soon, Rex was starting to get restless. Pulling his thoughts back to the present, Six pulled the dark-haired teen's arm over his shoulders and started to slowly pull him into a standing position. Six flinched internally as Rex groaned in pained protest at being moved, but he could feel the younger man try to help by getting his feet under him.

"Six?"

"Easy, Rex, I have you. I'm going to take you to Holiday," said Six, as he made sure he had a good grip on the dark-haired EVO. "Bobo, go make sure the doctor has a bed ready for him."

"Ya got it!" agreed the chimp as he ran off ahead of them.

Doctor Holiday looked up from spreading the last sheet on the med-bed to see Six slowly come through the door supporting a weak and hurting Rex. Getting a nod of greeting and a raised eyebrow at the absence of a certain monkey, she watched him bring the younger man over and help him sit on the edge of the bed. Placing a steady arm around the boy's shoulders, the green-suited man helped Rex stay upright, as Holiday gave him a pain pill and a glass of water.

Taking the glass back, Holiday walked over to her work bench, and began to gather her reports together, while watching the other two in the monitor by her side. She saw Six help Rex lay down, before pulling the covers over him, and hesitating only a second before he began to gently card his hand through the boy's hair. As the younger man sighed in contentment, she could see when his body completely relaxed into a restful sleep. This is why Holiday had sent Bobo on an errand for her, she knew that Six would never have comforted Rex like that if anyone but she was present. After all she had caught the agent doing these little things for Rex too many times for him to care if she saw more, but she still tried to give him the illusion of privacy when she could.

"Agent Six, come in."

"Six here, go ahead." Holiday turned to see Six stepping away from the sleeping Rex, his fingers to his ear piece.

"We've discovered more of those strange readings, sir."

"Understood. Get a team together, I'll be there in five minutes." Cutting the connection, Six looked over at her before raising an eyebrow.

"Don't worry, Six. I'll keep an eye on him."

The stoic man nodded, before glancing one more time at Rex, then turning, he walked out of the room.

Hours later, Rex sat on the med-bed tapping his fingers nervously against the data pad in his hand. He had only woke up about half an hour ago and was shocked to find out that none of Six's team had reported in for over three hours. Holiday had gone to the command center (after getting Rex to swear that he wouldn't move) to see if there was any news on the team. Rex growled in frustration before dropping the pad, drawing his legs up to his chest, and dropping his head onto his knees. He should be out there helping Six, not stuck here where it was 'safe'. How could he make sure Six was proud of him, that the agent never regretted sticking his neck out for him, if he was sitting here being useless?

"You're not useless, Rex."

Rex stiffened at the sound of Six's voice (mortified that he had been talking out loud again) and just listened as the agent's footsteps approached. As he got closer, the teen couldn't help frowning a little thinking that something sounded off about the older man's steps.

The young EVO didn't look up as the older man stopped next to him. It wasn't until he felt a surprisingly gentle hand rest on his bowed shoulders that Rex worked up the courage to lift his head and look at the older man. Seeing the faintest of smiles on Six's face, the teen felt himself completely relax.

"You're never useless, Rex, and I'm always proud of you. Well…"

Rex, who had been grinning at the agent, felt the smile slip at the thoughtful look on the man's face.

"Maybe not during that incident in Peru, or that time at those talks in Rome, defiantly not during the summer in Spain..."

"Ok! Ok, I get the idea!" cut in Rex, his face heating up with each event that Six listed. Still, he couldn't help the smile that crossed his face as the normally stoic man ruffled his hair. Seeing the small, answering smile on the other's face, Rex closed his eyes and allowed himself to soak up the affection that Six was giving him. The dark-haired EVO knew this open show of caring wouldn't last much longer. In fact, there were only two reasons that Six would be freely showing it now; one, there was no one else in the room but him and two, the sneaky agent had temporally disabled the cameras in Holiday's lab, which he just knew was driving the techs nuts.

"Rex." The younger man could hear the note of warning in his mentor's voice, and knew that their time was almost over. So acting on impulse he reached out and hugged the older man around the waist. Since he still had his eyes closed, Rex missed the total softening of Six's face as he reached down to return the hug. Far too soon, Rex felt Six try to gently pull away, and sighing in regret the younger man opened his eyes before sitting back on the med-bed. Six offered him one more brief smile before his mask once more fell into place.

"More samples for the Doc?" asked Rex, as he finally noticed the container hanging from Six's hand.

"With the strongest signal we've found yet," said the agent, giving the teen a small nod of approval before turning and walking over to place it on a nearby work bench. As he placed the container down, Rex finally saw the blood staining the left leg of Six's pants.

"Six, your leg!" cried Rex, as he jumped off the bed and rushed over to the ninja's side.

"It's not that bad, Rex. They sent some green recruits with us and they froze up when they saw the Fusions we were up against. One of the things got a lucky shot in when I was keeping one the newbies from getting himself killed. They also managed to take out our communication equipment. It's looks worse than it really is, so there's nothing to worry about."

Seeing the sweat that was forming on the man's face, and the way he was holding onto the table, Rex merely shook his head, and grabbing the agent's arm starting pulling him towards one of the bed.

"I think we had better let Holiday decide on that."

Several hours later, Rex sat on his own bed watching the older man sleep. The wound had been worse than the green-suited agent let on. Fusion matter had infected it, and had been slowly spreading through his mentor like poison. Thankfully DexCorp had discovered an antidote for infections like the agent's, and the older man was now resting. The teen couldn't help but smirk when he remembered that to keep Six in bed, Holiday had hidden his glasses and jacket.

Just as Rex decided to have a quick doze himself, Bobo walked into the room holding a small data pad. Throwing a brief, concerned (though if you ever confronted him, he would have denied it) look toward the sleeping agent, the monkey walked over and handed the pad to Rex.

"Don't ask how I got it. You're better off not knowing, but you own me five banana milkshakes for this."

"Right. Thanks, Bobo."

"So why did you have me take that data?" asked Bobo as he watched Rex access the pad.

"These are the coordinates of where each of those strange samples came from. I'm hoping maybe I can find a pattern or some link. The sooner we find a link, the sooner I can get back to normal, and…" Bobo watched as the teen glance up at Six, before going back to the pad. "I'm tired of people getting hurt because I can't do my job."

Seeing the miserable look on Rex's face, Bobo opened his mouth to say something he hoped would be comforting, when the teen gave out a shout of success. Turning the screen toward the monkey, Rex showed him what looked like a map of a tunnel system.

"See, Bobo, when you look at a map of the sewer system, all the sample locations are the same distance from this one area here. So you and me are going to check it out. Great huh?"

"You sure we should be doing that, Chief?"

"Come on, Bobo, where's your sense of adventure? Besides all we're going to do is see if anything is down there. If there is we call in Providence to back us up. If not, than we save them a little search time. So what do you say, huh?" asked Rex.

"I'm game. It'll be better than sitting around on our butts all day." Nodding in agreement, Rex threw off the sheet, and they quietly slipped out of the med-bay. As the door closed behind them, neither EVO saw Six's head turn toward them his eyes opened into slits.

An hour later, Rex and Bobo were nearing their destination, but neither of them was happy. They had not come across a single Fusion on their way down, and it was putting them on edge. Entering what they now realized was a spillway; the two EVO's froze in shock. In the middle of the spillway was the portal for a Fusion Doppelganger.

"Bobo, we need to leave, we need to leave right now!" shouted Rex as every instinct he had screamed at him to run.

"You'll have no argument from me," said the chimp, as he began to back out of the room.

Turning, Rex was about to run, when he heard something rushing up behind him. He didn't even get his head turned before he felt something jump on his back slamming him to the ground. The last thing he heard before blacking out was Bobo franticly calling his name.

"Rex. Rex, wake up. Now, Rex!"

Being used to obeying that voice in that tone, Rex forced himself to break free of the darkness that was calling to him. Slowly opening his eyes, Rex groaned as his head began to pound. Feeling something squeeze his shoulder, the teen looked to his left and blinked in surprise to see Six crouched beside him. He had one hand on the teen's shoulder, the other holding his katana defensively in front of them. At first, the only thing that Rex noticed was that Six had found his glasses, but still was missing his jacket, and then he finally noticed the agent's tense posture. Taking his first good look around, the younger man felt the blood freeze in his veins as he drew in a sharp breath. He saw that he was no longer in the well-built sewers of Downtown, he was now in the slime-covered corridor of a Fusion's lair.

Suddenly wanting to be anywhere but here, Rex swiftly gained his feet, and after shaking off some dizziness he helped the older agent up. He started off to the left, only to be stopped by his mentor and pulled toward the right. Deciding Six probably knew the way better than he did, Rex followed along without a word of protest. They had been walking for only a few minutes when they came to a clearing and Six pulled up short. Looking around the tense agent, Rex felt suddenly sick at the sight in front of them. It was Rex, but only not really, Fuse had made a Doppelganger of him. The thing in front of them was obviously spoiling for a fight, its eyes full of hate as it smashed the ground with its smash hands.

"Rex, take this and give me cover fire," ordered Six as he handed the teen a null-void pistol. "And whatever you do, DON'T use your nanites."

Rex nodded at the older man, suddenly very grateful that Bobo had been helping him with his aim. The young EVO knew he would never forgive himself if he hurt the agent that was fighting for him.

Minutes-but what felt like hours-later, the Fusion gave a final cry before destabilizing and sinking into the ground. Locking eyes with the huffing agent, Rex grinned as he was given a nod of approval before Six's head snapped up as if he had heard something.

"We need to go, Rex," ordered Six as he began to push his charge toward the portal.

"But, Six, your leg. Shouldn't we rest a-" started the teen, only to be cut off by a hard push from his mentor.

"Now, Rex."

"Ok, ok, quit shoving," huffed the young EVO as he ran ahead of the older man. Being in front, the dark-haired EVO didn't see the Senior agent look back, a resigned but determined look crossing his face. Turning back and seeing the portal getting close, Six made his decision.

"Rex, I want you to remember something. Even if you forget everything else, remember this; I have always been proud of you, and I have always cared about you."

As Rex started to look back in shock, he felt something slam into him, throwing him toward the portal. He was just able to catch a glimpse of Six fighting with his own Fusion, and then the portal whisked him away.

Appearing back in the sewer, Rex hit the ground hard and rolled for several feet. For a minute, all he could focus on was getting the air back into his lungs, and ignoring the pounding of his head. Slowly pushing himself up onto his knees, the shaky teen placed a hand to his head before looking toward the portal. Or rather where the portal had been.

"Six?" weakly called Rex, as he looked around for the older man. As he started to crawl to where the portal use to be, he continued to call his mentor's name, each call a little louder, a little more frantic then the last. Until finally he stopped, the terrible truth choking him. His guardian had never made it out of the Fusion's lair.

"SIX!"

* * * * * * * * *

"That's all that I know. That little bit is all I managed to get it out of Rex just before he passed out," reported Holiday as she faced the view screen. Staring back at her were all the leaders of the Earth's Combined Forces. Ben, Dexter, Number One, and several others wore varying looks of concern, as they listened to her report.

"My condolences on your loss, Dr. Holiday," said Dexter.

"How's Rex doing?" asked Ben, his worry evident.

"He...when he woke...his nanites..." Holiday looked over at the windows of her lab, and briefly watched the teen standing in front of them. His face was carefully blank, and as she watched she saw him look around and spot a (to her) familiar jacket. Going over to the chair it was on, she watched as he just stared at it.

"I always thought something traumatic could trigger it, I just never thought it would be an event like this. I think to protect Rex from the pain of losing Six, his nanites erased his memory. Of course that's just my theory. I'm still not fully sure what causes these episodes, but the Rex that we knew is now gone," reported Holiday, her voice thick with sadness.

"So you mean he doesn't remember anything?" asked Number One, a hint of sadness and fear infusing his tone.

"When he woke up, Rex said he only remembered two things," said Holiday, as she saw Rex pick up the green jacket up off the chair. As she watched him stare at it, she noticed a surprised look crossed his face. She understood why a moment later when he reached up and wiped tears from his face. She knew he didn't understand why he was crying over a jacket, or why he seemed to clutch it tighter as he turned back to the windows.

"One of those things of course was his name," started Holiday, before she finally turned from Rex and looked back at the screen in front of her. The feelings of loss and sadness clear for everyone to see in her eyes "The other, is a man's voice telling him that he was always proud of him, and that he had always cared for him."

Over by the windows, Rex wiped the last of the tears from his face, before once more looking at the jacket in his hand. Looking up with a blank expression, he slowly slid the green jacket on. Its steady weight a comfort that he knew he would never understand, nor one that he would ever give up.