Disclaimer: I don't own Star Trek 2009 or anything related to Star Trek. Though I wouldn't mind spending an evening with Kirk or McCoy, but that's another thing.

Author's Note: I've always wanted to write a kid-fic and I couldn't help myself. There will be lots of whump and hurt/comfort. This will not be a slash fic, but it will include friendship between Kirk, McCoy, and Spock. It almost might include hints of Spock/Uhura. This is unbetaed, so please forgive any mistakes. Enjoy!

This is set after "Into Darkness". There is some swearing. Bones does like his colorful metaphors.

Chapter One

"Damn it Jim, don't touch it!"

Doctor Leonard McCoy continued to run the tricorder over the injured ensign as he listened to the laughter over the comm. The plasma injury was minor. The doctor administered a hypo of analgesic. He motioned for Nurse Chapel to assist him with the dermal regenerator. Captain Jim Kirk continued to laugh. He was on the surface of the uninhabited planet with Commander Spock, Lieutenant Uhura, and Ensign Talcott as they studied the transformation of a rare flower. Jim said something to Spock before speaking into his communicator again.

"Don't worry, Bones. I'm not gonna touch it." There was a pause and Spock's voice was muffled in the background. "You know Bones, this would be much easier if you weren't checking up on me and I wasn't wearing this damn medical bracelet."

"And you should still be lying on a bed in the medbay. The medical sensor is permitting you to be on the away team. You're still recovering from the Tarcalian flu. If you weren't allergic to the cure, we wouldn't have to worry about it."

"It's only some lingering nausea. I don't think it requires a medical bracelet."

Leonard shook his head and motioned for Chapel to finish up with the ensign. He moved into his office and picked up the PADD on his desk. His body ached as he finally sat down. "You also have a slight arrhythmia. I should have strapped you down to a biobed."

"I know. This is a once in a lifetime opportunity to see the transformation of the Tula flowers. I'm grateful you allowed me to come down. Really."

"Yeah, just be careful."

"I always am, Bones. Kirk out."

Leonard shook his head. "Careful my ass."

He went back to work, studying the chart in front of him detailing the most recent injuries and illnesses among the crew. Most were engineering mishaps. They were all fairly routine minor medical emergencies. He entered the information into his PADD for his report to Star Fleet Medical and headed back into the medbay to check on his patients. He only had two still recovering from the Tarcalian flu and both were expected to be discharged that evening. It would be a nice reprieve from all the cases he'd experienced before he'd had a chance to create a vaccine for the rest of the crew. Jim was one of the last to come down with the fever and extreme nausea. He'd been discharged that morning under the condition of the medical sensor and he had to check in once the away mission was completed.

The doctor checked up on his remaining patients, pleased with their recovery. He busied himself with other things, making a list of things to inventory when the last patient was discharged and before another engineer could have an accident. Two hours passed before he knew it. The doors to the medbay opened and Ensign Chekov hesitantly walked in.

"What can I do for you, Mister Chekov?"

The younger man shrugged and moved toward the biobed as Leonard pointed. Chekov took a seat, glancing around and looking uncomfortable. Leonard pulled out his scanner.

"I haz a headache."

Leonard frowned and his tricorder whirled softly as it worked. There appeared to be some stress in his frontal cortex.

"I can treat it. I suggest you get some rest and come see me if this doesn't make it feel better."

He fetched an analgesic. After he inserted it into the hypo, he injected in Chekov's neck and dismissed him. Chekov thanked him, promising to get some rest. At least someone on the Bridge actually responded when their health was in jeopardy. Kid really was a genius. Leonard returned to his inventory. He stopped when he heard a ping from his PADD; Jim's medical sensor had been triggered. He reached out and quickly pulled up the captain's stats and saw his heartbeat was irregular.

"McCoy to Kirk."

It was Spock who answered. "Doctor, the captain is experiencing some dizziness and confusion."

"Spock, I'm fine. Really." Kirk's voice was a little shaky.

"What's he doing?" Leonard interrupted.

"The Captain is sitting with his head resting in his hands. Is it your medical opinion we should cancel the rest of the mission?"

Leonard took a moment to think. He knew Jim really wanted to see the flower's transformation and he noticed his vitals were already stabilizing. He rubbed his forehead. "What's he doing now?"

Jim answered this time. "I'm standing up and I'm fine. No more dizziness."

"Alright. I won't pull you now, but if your vitals set the alarm off again I'm pulling you out of there."

"Understood, Kirk out."

The doctor returned to his task, cursing under his breath. He better not regret this.

"Spock to Doctor McCoy!"

The Vulcan's voice jarred Leonard's attention and he immediately looked up from the drawer of medical supplies.

"McCoy here."

"There is a medical emergency. We are beaming aboard. Please meet us in the transporter room."

"Understood. Who's hurt?"

Thunder rumbled in the background before Spock answered. "The captain."

Leonard grabbed his medical kit and ran toward the transporter room as fast as he could. The doors slid open as he entered the room. The away team materialized on the pad. He laid his eyes on Spock, Lieutenant Uhura, and Ensign Talcott. They were all soaking wet and shaking slightly, though the Vulcan seemed less affected. Leonard quickly realized Captain Kirk wasn't with them.

Leonard opened his mouth to say something, but stopped when he heard the soft crying. He hadn't noticed at first, but Spock held a squirming bundle in his arms. It was a child not more than four-years-old; a small little boy with blond hair and bright blue eyes. Jim's eyes. He was dressed an oversized yellow command shirt and two black socks, which were sliding off of his tiny feet. The cries turned into screams as Spock tried to adjust his hold on the little version of their captain.

"What the hell happened?" Leonard demanded, pulling out his tricorder and scanning the kid.

Jim took one look at the doctor and put out his arms. His lower lip trembled. Leonard raised one eyebrow before putting his tricorder away and taking the soaked kid into his arms. Jim buried his face in Leonard's uniform and he felt the moisture through his shirt. Leonard rubbed his back in an attempt to calm him down. He looked at Spock before turning and heading toward the medbay. Spock and Uhura followed close behind him.

As soon as they entered the medbay, the doctor ordered Chapel to bring him a warm blanket.

"Jim, it's okay." He continued rubbing the boy's back.

Jim's cries grew quiet and soon he was left hiccupping softly. He kept his face nuzzled against the doctor's shirt. Leonard didn't even flinch as one of the hiccups became something else and Jim vomited all over the both of them. The little guy whimpered.

"It's okay, kid."

He carried Jim over to the nearest biobed. Leonard pulled the ruined shirt off of the boy as Nurse Chapel used a sonic cleaner to remove the emesis from the captain's skin. Jim helped kick the socks off his small feet. Once Chapel finished, Leonard wrapped the boy in the warm blanket. He activated the screen above the biobed and stared at the readings. Jim's heart rate was still irregular. The screen showed he was in pain and his body was stressed. He pulled out one of the medications Jim wasn't allergic to, along with a sedative, and gently administered it to his best friend.

"You're gonna be okay, Jim." Leonard gently ran his fingers through the boy's hair as his eyes grew heavy, but he fought to keep them open. "Get some sleep. I'll be here when you wake up."

The blue eyes slowly closed. Doctor McCoy pulled the privacy curtain around the biobed and instructed Chapel fetch him a clean shirt as he took a blood sample from the kid-sized Kirk. He turned his attention to the First Officer as he worked.

"What the hell happened down there?" Leonard cleaned his hands on the towel one of the nurses brought him.

Chapel brought him a clean shirt and waited for him. Not caring about decency, he stripped off the soiled clothing and handed it to her to be destroyed. He pulled on the clean medbay uniform top as Spock spoke.

"We were observing the transformation of the Tula flowers when one of the small flowers emanated a white light and spit out a clear substance. Captain Kirk was standing close to it. He was sprayed with the liquid and for a moment appeared normal." Spock glanced at the small child. "He then screamed and fell to the ground. The light engulfed him for a moment and when he became visible, I immediately noticed the change. The weather quickly changed to a storm and we contacted you."

"I'll need a sample of the substance," the doctor interrupted.

"Ensign Talcott took a sample before we beamed up. I will make sure he gets it to you at once."

"Is the captain going to be okay?" Uhura's voice trembled as she watched the small boy's chest rise and fall.

"I don't know. I need to examine him." Doctor McCoy glanced up at the visual screen. "I'll let you know when I know something. Make sure all of you change and clean up. M'Benga can give you your post mission physicals."

Spock nodded and the two left Leonard alone with the suddenly young Captain. He went right to work. Jim's blood pressure was 100/68 and his body temperature was 99.5 degrees, a little high but not serious.

"Christine, see if you can find some clothing for him and get him cleaned up." He ran hand over his forehead. "I'll need to analyze the substance in his blood to see if I can figure out what the hell happened."

"Yes, Doctor."

Leonard stood for a second. Jim shifted slightly and curled up into a little ball. His pain indicators had level offed, but he was still restless. Christine came over with a small scrub top and pants. They were enormous on his small body, but it would have to do until he figured something else out. Leonard helped her dress him, noting he could see all of the kids' ribs. The head nurse put a hand on his shoulder before leaving him alone. Leonard had to find a way to fix this.

Leonard watched as Jim trembled beneath the blanket and poked his head out. His blond hair was tousled, but he was wide awake. He sat up a little bit. A brief look of pain crossed his features, but the kid quickly suppressed it. Jim picked at the blanket with his fingers, but didn't talk. He glanced up once at the doctor and gave him a small smile. The poor boy was painfully timid, the doctor noted. Jim pushed back the blanket and crawled down the biobed toward Leonard.

"Who are you?" his small voice inquired.

"My name is Doctor McCoy, but you can call me Bones if you'd like."

Jim smiled. "Bones is a silly name."

"What's your name?" Leonard sat up straighter as the boy moved to the edge of the bed and danged his legs.

The kid stared at Leonard. "James T. Kirk, but you can call me Jim or Jimmy."

"Doctor McCoy, how is the Captain?" Spock stood at the edge of the curtain.

Leonard started, almost falling from his chair. Jim squealed, crawling down the bed and pulled the blanket over his head. Spock simply raised an eyebrow.

"It took him ten minutes to come out the first time!" Leonard said, pulling the curtain closed and leaving Jim alone.

"I am sorry, Doctor. I only meant to inquire to the state of his health." The first officer tucked his hands behind his back.

Leonard ran his fingers through his hair. "He's a little malnourished and small for his age; he's only twenty-eight pounds and thirty-eight inches tall. He's underweight. Jim's fever is lower and I finally corrected his heartbeat irregularity. Physically, Jim is a normal four-year-old, though he is quite small." The doctor hesitated. "Emotionally, he's young and I suspect… he was emotionally neglected. It's not serious since he does try to communicate and reach out, but it would make sense regarding his low weight. Though with his list of allergies, I suspect Jim was a picky eater as a child."

Spock seemed to ponder the details. "Is it your medical opinion the captain has been reverted to his condition at a previous age?"

"Yeah. Other than that, I have no idea what happened. I'm still working on the substance Ensign Talcott provided."

"Do you believe the condition can be reversed?"

"How the hell should I know? I don't even know what happened!"

"Bones!" Jim's small voice sounded scared.

Leonard turned, quickly pulling the curtain open. Jim sat on the bed with his arms around his middle and making a face. The doctor grabbed an emesis container as the little boy puked up the meager contents of his stomach and let out a soft sob. Leonard rubbed his back, whispering softly. Nurse Chapel took the bowl away when he finished and Jim moved quickly. He stood up and jumped into Leonard's arms. The doctor almost dropped him in surprise, but held the small boy against his chest and continued to rub his back as he cried. He glared at the Vulcan.

"What the hell are we gonna do?"