Donatello finally emerged from his laboratory around midday the following day, looking exhausted and unsteady on his feet. Raphael immediately leapt off the sofa to come to his purple banded brother's aid.

"You ok Donnie? How's Leo?" said Raphael, expressing concern.

"Leo is resting up, dosed up on painkillers. His tail has grown longer overnight, and his skin appears to be darkening. I've been running some blood tests and it looks like Leo has been infected by a substance that's changing his physical anatomy. Most definitely from that dart you mentioned. I'm not sure how far this will go." Raphael had no words. He was the one in charge whilst Leo was out of action and he had no idea what to do, or say.

"Can you fix this?!" he exclaimed.

"Well, I would like to run some tests on you and Mikey if that's ok. After all, you were darted, and unfortunately Mikey's skin irritation is running rampant over most of his body now. He may still be having an allergic reaction to whatever was in that substance. I don't really want to give him steroids unless I really have to. Ideally I would need a sample of what was in that dart, but I admit it would be too dangerous to go back to the facility. How are you feeling anyway?"

Raphael was struck by the question. In his mind he felt fine. Other than the fact he hadn't slept all night as he was keeping watch over Mikey and trying to peek in on his two other brothers now and then.

"Donnie, I feel fine. Don't worry about me. You should be worrying about Mikey and Leo. They need you. I need you."

Donatello was quite taken aback by Raphael's confession.

"Thanks Raph, but just to be safe, please can I do these tests?" Raphael sighed, but nodded.

The two brothers walked in to the lab; printouts of tests results and documents splayed out across two different tables, one that used to be Donatello's less chaotic work space. If Raphael looked at any of them they may as well be written in a different language. As soon as he entered the room he scanned the vicinity for his older brother. His heart rose to his throat as he saw an almost unrecognisable form lying limply in a cot in a corner of the room. Raphael instinctively raced over to his brother's side and froze. Instead of an emerald colour, Leonardo's skin had darkened somewhat to a dark forest shade of green, matching his newly emerged tail. It was overhanging the side of the bed as well as two IV bags helping to supplement his brother's weakened body.

How could I let this happen? Raphael was drifting through his self-punishing thoughts when Donatello interrupted him.

"Raph?"

"Hmm?"

"Could you come over here please?" Raph did not want to move, fearing his beloved leader would slip away if he took even one step back.

"Raph." Raphael swallowed and reluctantly turned towards Donatello. He took a seat and hunched over glumly as Donatello extracted a vial of blood from Raphael.

After a rather long half hour waiting for the sample to be processed in a centrifuge and analysed on Donatello's computer, the scientist reported back.

"You have abnormally high levels of cortisol. I would blame it on recent events as it does normally result from stress, however I am concerned that this could be a result of being darted. How have you been feeling? Any pain, nausea, dizziness?"

"You asked me that already." Donatello pulled a face.

Raphael looked away, trying to think before he spoke (which was unusual for him).

"Donnie, really, I feel fine. Just worried about the guys." Donatello screwed up his face – he was unconvinced.

"Okay, okay. I maaaay not have been sleeping that much over the past few days. When I sat with Mikey last night I thought I was gonna drift off, but I didn't. I didn't even feel sleepy. I kept thinking…"

"I could administer some artificial melatonin to help you get to sleep. It will hopefully help the body to realise that it needs to rest."

"Maybe you should give some to Mikey to calm him down. He was pretty upset last night."

"It's not a sedative, Raph, just something to help you get some REM sleep."

"And what about you, Donnie? Are you ok? You look like you could use some of that melstuff as well." Donatello shrugged and turned away.

"I have a lot to figure out, Raph."

"We need you to fix this, Donnie. You're the only one that can."

"I…I don't know if I can." Donatello almost succumbed to the onslaught of guilt but battled through the tears threatening to tread down his face.

"I know this is not a good idea, but we need to go back to the facility. If I can find those samples the Kraang hit us with, maybe that will give us some answers."

"I can't let you go alone, Raph. Can we at least wait until Leo is conscious before we make any rash decisions?"

"Donnie, we don't know when that will be. Why do you always support Leo over the rest of us? Like you said, we don't know what's gonna happen, which is why we need to find the answers now! I suggest you stay here with Leo, whilst Mikey and I head up top."

"I can't let you do that, Raph." Donatello took a defensive stance as he prepared to reach for his bow staff.

"Seriously, are we gonna fight over this?"

"Yes, we are. I am trying to save our family, and I don't need a self-destructive influence to sabotage my efforts."

Raphael was exasperated - the first time he had felt this way for the past few days. He felt good to let go; he grabbed his sais and launched himself at Donatello who predictably blocked his attack. Although he placed his full weight forward, he felt himself beginning to slide backwards - friction wasn't on his side. Raphael pushed him away and composed himself for a second launch. Donatello flipped back over his desk which the red banded brother collided in to. Passion was on Raphael's side, but unfortunately for Donatello so was anger. He leapt over the desk in pursuit and kicked behind his younger brother's knees, causing them to buckle and give way. He pinned down his victim and forced his forearm against Donatello's neck. Bright green eyes met the sadness and fright of brown, however their glares were not interrupted despite the sudden and excited outburst from their youngest brother.

"Yo Donnie, Raph, come look at me, woohoohoo!"

*Author's note* - thank you for your support so far, especially as this is my first story. Special mention of Yukio87 for your enthusiasm and support and the guest who left the review =)