A/N: I wrote this story for the NFA SeSa Fic Exchange. The quote below is the prompt I was given, and it was written for DNAchemLia, who loves supernatural and horror stories. So this is a horror story of sorts. It plays off a fear that I myself have had to varying degrees since I was young. There is a case in this, but it's definitely a horror story, using a lot of the classic horror story motifs...but without the gore. :)

Disclaimer: I do not now, nor have I ever, owned NCIS, and I'm making no money off this story.

I'll Be Watching You
by Enthusiastic Fish

"It's not a matter of whether or not someone's watching over you. It's just a question of their intentions."
Randy K. Milholland

Chapter 1: Prologue

27 years ago...

"Tim, where have you been?"

Tim shrugged. "In the bathroom."

"What for?"

"I was playing with Mit!"

"Who's Mit?"

"He lives in the mirror. He's me, backwards!" Tim grinned.

"Tim, that's only your reflection."

"I know."

His mother knelt on the floor in front of him. "Tim, I know this move has been hard for you, but you won't make any friends if you stay inside all day, staring into a mirror."

"But...but some of the kids out there aren't nice. Mit is there every time I look in the mirror."

"Tim, you need to make some real friends. Not everyone is going to be nice, but that's always the way it is. Actually, I was just about to go next door and meet our neighbors. Why don't you come with me?"

"But I promised Mit I'd go back!"

"Tim, Mit is just your reflection. He's not real."

"Okay." Tim took a deep breath and nodded.

x.x.x.x.x.x.x

Two years later...

The Christmas tree was beautiful that year. Tim's dad was actually home for Christmas, and with a new baby in the home, it was nice to feel the peace and contentment that came from being together as a family.

Janene paused as she glanced at the Christmas tree. There was a new present. When had it been put there? Wait, there were two new presents. She knelt down and picked them up one at a time.

To Tim. From Mit

To Mit. From Tim

She was surprised to see the presents. She had thought that Tim was over all that nonsense.

"Timothy!" she called.

"Yeah?"

"Come in here, please."

"I can't!"

"Why not?"

"I'm...playing with Mit."

"Timothy McGee, you get right in here this minute!"

Her demand was rewarded by running feet. Tim came into the room and saw the presents in Janene's hands.

"What is this, Tim?" Janene asked.

"Christmas presents," Tim whispered.

"Tim, we've talked about this. You can't keep pretending there's a person in the mirror. You're taking these back to the store."

Tim's eyes widened and he seemed almost afraid. He shook his head.

"I can't!"

"Can't? Why not?"

Tim looked around and then leaned in close to her with the expression of one about to reveal a protected secret.

"Mit will be mad at me," he whispered.

Janene looked at Tim with growing concern. This wasn't an act. Tim was genuinely afraid. More than that, he seemed actually terrified at the prospect.

"Tim, there is no Mit."

Tim's lower lip began to tremble. "Y-Y-Yes, there is. I thought...I thought he was my friend, but...I don't like him anymore!" He started to cry. "I'm scared of him, Mommy! I don't like him...but he's in all the mirrors and I can't get away!"

Janene quickly put down the presents and took Tim in her arms. He was shaking with fear and he hadn't called her 'Mommy' in ages.

"He makes me do things, things I don't want to do...but I have to..."

"Tim, it's just your reflection. It's not..."

Tim nodded and buried his face in her shoulder. "Yeah...my reflection. He's my reflection!"

That Tim was terrified, Janene couldn't deny...but why? What had changed his imaginary friend into something so sinister? ...and what in the world could she do about it?

"Tim?"

No reply.

"Can you let go of me, just for a minute?"

Tim did, albeit reluctantly. He looked around the room again. No mirrors in this room, and Janene remembered, now, that he'd been spending a lot of time in here, even ignoring his computer (the monitor would act like a mirror), choosing instead to read detective novels. How had she missed this cultivated terror?

She walked into the kitchen and picked up the phone. She called Michael and told him about Tim's sudden fear as quietly as she could.

Michael was home in ten minutes.

That evening, they sat with Tim in the living room. Janene was holding Sarah in her arms, rocking her...as Tim sat close to his father, telling in great detail all the things that "Mit" had said and done.

Afraid, not of "Mit" but that Tim was suffering from some kind of mental illness, Michael and Janene chose to take him to a psychiatrist.

The first of many visits.

...and in the meantime, they took down all the mirrors in the house except in their own bathroom.

x.x.x.x.x.x.x

Six months later...

"Okay, Tim. It's time to try it."

Tim shook his head over and over again.

"No. I don't want to...see him."

"He can't hurt you."

"Yes, he can! Just because you can't see what he does doesn't mean he can't hurt me!"

"Tim, listen to me. We've talked about this a lot. Remember that Mit only has as much power as you give him. If you tell him that you won't play with him anymore, won't see him anymore, then your reflection will go back to being just your reflection. I'll be right here with you. You just need to look into the mirror and tell Mit that you don't like him anymore and that you don't want to see him anymore."

Tim shook his head again.

"Don't let him see that you're afraid. Just tell him."

Tim looked down and then nodded.

"...but he won't come if you're here. Mit only comes out when I'm alone."

"All right. I'll be right outside the door."

"Okay."

Tim took hold of the hand mirror and looked at the psychiatrist. He nodded encouragingly and then stepped out of the office. Tim took a breath and looked in the mirror.

"I..."

He almost started to cry.

"I don't like you, Mit! You're mean! You're bad! And I'm not going to play with you anymore! Stay away! Go away! I don't want you in my mirrors!"

Then, Tim threw down the mirror and it shattered into pieces. He backed away from it and hid in the corner. His parents and the psychiatrist came in and his parents comforted him until he stopped crying.

Two days later, they found Tim walking down the middle of the road at three in the morning. He was asleep. When they woke him up, he told them that Mit was trying to take him away to his place and that he hadn't wanted to go.

Back to the psychiatrist.

Another year of therapy and they had convinced Tim that there was no Mit, that his reflection was just his reflection, that there was no evil twin lurking and trying to take him away from his family.

When it came down to determining the cause of Tim's hallucinations, the psychiatrist said that they needed to get him some hobbies, that Tim needed stability rather than moving to different bases every few years, and that they needed to make sure he had friends.

They took his advice to heart and Michael decided to take a desk job. It was a comedown for him, but if Tim's mental health depended on it, it was worth it.

Tim had nightmares sometimes, and occasionally, he would walk in his sleep, but those events decreased in frequency as he got older. He was never particularly popular in school. He was teased and bullied because of his awkward, quiet ways, but he was able to persevere.

...and Mit eventually faded from his mind, becoming nothing more than a vague, disturbing memory.