Leonardo was in the middle of a calming breath when he heard footsteps rapidly descending the basement steps. A flicker of annoyance lit across his mind, but he strove quickly to contain his irritation at the interruption.

"Leo!" Jenna's voice carried around the corner of the staircase before he had a chance to see the woman. "Is Donny down here with you?"

The blue-masked turtle got to his feet, abandoning hope of returning to the relaxed position for the time being. "No, I haven't seen him all day, Jen. I know he was working - did you check the Lab?"

The young woman looked exasperated. "Of course I looked there, and just about everywhere else! The other girls are helping me comb the house, but nobody's seen him since this morning."

"That doesn't make any sense; he has to be somewhere. We're good at disappearing when we need to, but we can't vanish into thin air. Did anyone look around outside?"

"Calley made a circuit of the property, but she didn't see him. Besides, people have been in the Great Room all day, Leo. He couldn't have left without someone noticing."

"That's not the only exit, Jen," he reminded her. "He could have gone out the back without being seen."

"Leo, that doesn't even sound like Donny. Do you really think he'd run off without even telling anyone?"

He shook his head. "He's not the type to hide as a joke either. This is weird," he admitted. "But he's got to turn up. I'll help you look for him."

Leonardo trotted up the steps, and heard Jenna's breathing quickening. "Jen, what's the matter?" he asked as he crested the stairs. "You sound..."

"Crazy? Is that what you wanted to say?"

"That isn't it, Jenna. What's going on?"

"I have a bad feeling about this, Leo. It doesn't make any sense."

"Did you talk to everyone? You're sure no one has seen him?"

"Well, yes, for the most part. Raph didn't want to wake up, I could barely get him to stir. Doc gave him a heavy dose of the entromine over an hour ago. I couldn't tell if Raphael even realized what I was asking him."

"But he's in the back of the house still, isn't he? Maybe he saw something."

"Leo, I told you. I couldn't get more than two intelligible words out of him."

The blue-masked turtle shook his head. "There's a way around it, Jen, there has to be." He turned away from the woman and headed for the Great Room. "Doc? Where are you?"

The blond-haired man was across the room, and spun on heel too quickly when Leonardo called him. Luke's grimace of pain made Leonardo wince too.

"Careful, Doc, I'm sorry for startling you. We need to wake up Raph from the entromine. Any suggestions?"

"Uh...cold water and a big stick? You might want to have your running shoes on first though...if he could chase you that is." Luke didn't seem like he was honestly trying to be funny, and no one laughed.

"I'll grab a bottle from the fridge," Jen volunteered.

"What are you trying to do with your brother?" Luke asked.

"I want to make sure that he didn't see Donny," Leo replied.

A perplexed expression came over Luke instantly. "We've been searching the house from top to bottom, Leo, and there's no sign of him. I don't know what he could possibly be doing."

"Do you think he needed to clear his head? You guys do have a lot going on right now between Raph, Mike, and Becky."

"He could have," Luke allowed. "But the only way that he's still in this house is if he's buried himself deep in hiding. I think it's more likely that he went outside, but I don't like that idea either."

Leonardo looked out at the moisture that was running down the glass windowpanes. "Is that freezing rain?"

"Take a step outside, Leo. Check out the coating of ice we already have on the trees."

"He wouldn't go out in this," the turtle said suddenly. "Don knows better."

"Then we need to start tearing up the floor boards, Leo, because I swear he isn't here."

Jenna returned from the kitchen and Leonardo motioned for her to follow him as he headed down the hall toward the back of the house. Luke trailed along with them, and hesitated a couple of feet away while the blue-masked turtle approached his brother's chair.

Leonardo started out very gently, wetting his palms before patting Raphael's face. "Raph? Bro, wake up."

The red-masked turtle mumbled something he couldn't understand, and turned his head away from Leo.

"No, Raph. Don't fight me - wake up." He shook his shoulder insistently this time.

His brother's irritation only appeared to increase as he resisted Leonardo's effort to rouse him. Leonardo looked at Jenna and held out his hand to take the water bottle from her. With a careful motion he dashed water over Raphael's face, and waited apologetically while the surprised turtle rubbed his eyes.

"I'm sorry, Raph. I need you to listen to me. Do you understand?"

"Leo, what are you doing?" he growled in return.

"We're looking for Don, and we can't find him," he answered. "Do you remember seeing him today?"

The red-masked turtle's brow creased in concentration. "I've been pretty out of it for a while, Leo."

"I know, but what about before that?"

At that moment Katherine emerged from the back staircase, and the suction created from the ventilation caused the door to slam closed behind her. Raphael jolted as if startled, but the disoriented look in his eyes disappeared with it.

"Donny. I saw him - he was here, Leo. He came down those stairs too."

"When was that, Raph?" Jenna asked.

Raphael looked at the woman as if she'd lost her mind. "Jen, I don't remember it like that. I was hardly awake, but I know Don was upset. He insisted he had to get some air, and I told him not to go-"

"Did he say anything about taking the scanner with him? Was he wearing any layers?" Luke interrupted.

"He wasn't wearing anything, and I don't remember anything about the scanner. I told him not to go, Doc, he wouldn't listen!"

Luke swore under his breath. "They couldn't find his scanner upstairs. Without that machine, we don't have a reliable way of tracking him."

"We probably don't need to track him," Leo said thoughtfully.

"Leo, it's too cold for him to be out gallivanting around without protection! He could get seriously hurt!" Luke insisted.

"That isn't what I meant, Doc, I'm going after him. My point is that Donny is a creature of habit. Even if he's upset, he's probably not running around haphazardly. He would head for an area that he knew, somewhere he's been before. He and I only made that one side trip, so my guess is, that's where he's gone."

"Bundle up then, and make sure that you take some things for him too. I need to get something from the Lab. Don't leave until I get back down here," Luke ordered.

As Luke started up the stairs, Raphael's fingers latched onto Leo's arm in a desperate grip. "Leo, something is really wrong. He looked like he'd seen a ghost or something. It was one of the weirdest things I ever saw."

Leonardo swallowed deeply. "I'm going to get some clothes. Let Doc know if he beats me back here."

He climbed to the second floor, and met Calley outside their bedroom door.

"Leo, what's happening?" she asked. "You don't look so good."

"I don't have much time. Raph said he saw Donny leave, and I need to get after him."

Calley followed him into the bedroom and dug his boots out of the closet while he was sorting through clothes. "Wear your duster too, will you? You're going to get soaked. Do you know where he went?"

"I have a general idea. I need to pack some things for him too. Can you find me his boots maybe?"

The young woman left the room and returned a couple of minutes later with the boots already in a bag. Leonardo stuffed another coat inside too, and pulled the bag over his shoulder.

"Leo, be careful."

He squeezed her arm as he went by. "I will, and I won't be too long. I doubt he would have wandered much farther than we did the other day."

Luke called his name before he could get to the stairs, and Leonardo saw the pain clearly etched in his face as he hurried.

"Stop, Doc, I'll come to you."

Luke held out an epi-pen to him. "Adrenal-heat. One click, okay? Give it to him just to be safe, no matter what state you find him in. When you really start to feel the cold, give yourself an injection too."

"Simple enough. I'll be fast, Doc."

"Please do. I'm heading back upstairs to find out what on earth he was researching. Bring Donny up immediately when you get back."

Leonardo nodded, slipping the epi-pen into his coat pocket. Jenna was waiting at the bottom of the stairs when he got there.

"Maybe I should go with you," she said. "I could talk to him..."

"Jen, I'll be faster if I go alone," he replied gently. "Don't worry. I'll bring him back."

"Then hurry please."

"I'll be back soon."

The blue-masked turtle pulled on the hood of the sweatshirt he was wearing under the duster. The hood wasn't going to do him much good after it got wet, but he guessed that it might be better than nothing. His boots crunched on the blades of frozen grass, and he was strangely fascinated by the crystalline layer of ice that had formed on all the solid surfaces.

Leonardo was at once grateful for the gift of the boots that the girls had gotten all of them for Christmas last year, but he hated the thought of his younger brother running around without them. He breathed away the anxious flutter in his stomach and started moving as quickly as the uncertain layer of ice upon the grass would allow.

He'd hoped that the trees would provide a little protection from the elements, but the wind was blowing the rain in sideways, so that it was still saturating his clothing. It didn't take long for the chill to start setting in, especially combined with the wind. Leonardo banished the thought of the cold, and dashed faster up the path that lead to the nearby mountain peak.

He shivered involuntarily as rain came into contact with his skin, despite the layers he was wearing. Following the path that he and Donatello had used before wasn't difficult, but it was far less comfortable today than it had been on that sunny afternoon. When the wind picked up again it lashed heavy pine branches from side to side, laden with the extra weight of the coating of ice. Leonardo ducked under tree boughs with a further sense of urgency to hurry.

What could have upset him enough that Donny would take off in a storm like this? It's sheer madness.

Leonardo wiped moisture off of his forehead, hardly containing a tremor that shook him to the core.

It has to be bad news. He must have found something...but what? Then again...if he didn't find anything, it could have upset him too, for a different reason. Shell, why couldn't he just talk to us? What good has running ever done anyone?

Leonardo sighed as the frustration filled his mind. The important thing is to find him. Everything else can wait. C'mon, Don, don't let me down. I know you wouldn't have gone much further than this...I hope.

The partial clearing that lead to the ridge they'd perched on the other day was in sight. Leonardo picked up speed and accidentally slipped on fallen leaves that were already covered in a thin sheet of ice. He swiftly recovered his balance and pressed forward. The ascent up the hill was harder than the last time, and he slid more than once as he tried to keep his boots planted underneath him. He'd nearly crested half-way when his feet shot out again, and he landed on his knees this time.

Leonardo rose gingerly and kept going, shifting the bag he was carrying to his other shoulder. He hurried through the edge of the tree-line to the open clearing on the other side. The blue-masked turtle exhaled deeply when he saw the outline of his youngest brother sitting on the ground. Relief was nearly overcome by panic as he rushed to get to him.

"Don?" His voice shook along with the shiver racing down his back.

Brown eyes met him mutely, and Leonardo sighed once more. First thing's first. Get him taken care of, questions later.

"I'm glad I found you. I've got a couple things for you, okay?"

Leonardo fished the epi-pen out of his pocket and injected his younger brother, before pulling back his soaking wet sleeve to inject himself. He shrugged out of the bag he'd been toting, and helped Donatello get the boots on before wrapping the coat around him.

"Now you've got to get up. C'mon," Leo urged him.

He braced his arms under Donny for additional support, cringing at how cold his exposed skin felt. The purple-masked turtle stood unsteadily, staring at the storm-tossed branches as though hypnotized.

"I'm going to help you, Don. We have to get down from here."

It took a small push to get the younger turtle moving, then Leonardo kept himself planted firmly behind him to make the trip back to the house.