Disclaimer: I do not own Lab Rats, Disney does. Excuse any mistakes in spelling and grammar or anything else that might not look right in the story.

Here's a new multi-chapter Lab Rats story I am finally writing up! Hope you like it!

Lab Rats: Three Little Lab Rats and a Babysitting Leo

Synopsis: A mix-up with the Neuroscrambler causes the Lab Rats to have the minds of two toddlers and a baby. With Tasha and Donald out of the house for the day, Leo now must become the babysitter of three teenagers turned to little kids. Can Leo survive the chaos that goes on and will he be able to fix his siblings before Tasha and Donald come home?

Chapter One: Neuroscrambler Accident

The Lab Rats and Leo were home alone for the day.

Tasha and Donald were out of the house for the day.

That can only spell one word: trouble.

-Lab Rats-

"So, Big D and my Mom are out of the house for the day. We can do whatever we want! What do we wanna do?" Leo asked his siblings.

"I want to go to the mall!" Bree exclaimed.

Leo rolled his eyes. Girls.

He turned toward his two brothers. "You guys don't want to go to the mall, do you?"

"No."

"I wanna go to the circus!"

Leo sighed. Typical Adam.

"We're not going to the circus Adam." Bree piped in.

"Aw…but I really wanted to go!" Adam whined.

"Too bad." Chase stated.

"How about we pick something simpler?" Leo suggested.

"Ooh! I know the perfect place! The library!" Chase enthusiastically replied.

"Chase, we've said this before and we're going to say it again. We aren't going to the library. That's your thing." Leo stated.

"I guess we could just stay home and do something." Bree added.

"Yeah."

"Let's do that."

"We can go down to the lab!"

And that's what everyone did, they took the elevator down to their secret underground lab.

Little did they know that's where all the trouble was going to happen.

-Lab Rats-

Chase was on Mr. Davenport's computer, most likely pulling another prank on him.

Adam was getting his fingers stuck in a ball of rainbow-colored yarn. He was trying to learn how to knit, but that wasn't working out too well.

Bree was brushing her hair casually sitting on the chair and watching from a distance.

Leo was making sure nothing went wrong.

"Chase! What are you doing on Big D's computer again?!" Leo ran over to his brother.

Chase smirked. "Pulling a prank on him."

Leo grabbed the keyboard from Chase. "Well, stop! We're supposed to not cause any disasters again, okay?"

Chase frowned and crossed his arms like a little kid. "Fine." He mumbled.

Leo smiled. "Good." He set the keyboard back down.

"Hey guys! Look what I found!" Adam called.

Chase and Bree turned their heads to see Adam holding up Mr. Davenport's Neuroscrambler.

"It's the Neuroscrambler!" Chase exclaimed. "Adam, where did you get that?"

"In the drawer here." Adam pointed.

"Are you sure you're supposed to be messing with that thing? Remember what happened last time we used that?" Bree asked.

"I remember. We turned Big D into a teenager then a toddler and then back again." Leo explained.

Adam grinned. "So that means it's safe to use!"

"No! No! No! Absolutely not!" Leo snatched the invention away from Adam. "I want this day to go without a hitch, you got it?"

"Oh, Leo, what's the harm?" Bree asked.

"Uh…a lot!" Leo blurted out.

Bree rolled her eyes and continued brushing her hair.

"Well, if we're all on the same page, I am going to go put this thing back in its-whoa!" Leo tripped and the Neuroscrambler went flying, hitting against the cyber desk, and activating.

It was pointed toward Adam, Bree, and Chase. Leo gasped.

"NO!" He lunged forward, but it was too late. The flash happened and Adam, Bree, and Chase stood there with confused looks on their faces.

Leo sighed. This wasn't what was supposed to happen! He quickly grabbed the Neuroscrambler and looked at it.

It erased fifteen years from Adam, Bree, and Chase's memories!

Oh that's just great.

Leo looked at his siblings nervously.

"So, guys? How are you feeling?" He chuckled.

"Me tall and strong!" Adam exclaimed.

"Why's my hand so big?" Bree asked, examining her hand intently.

"Goo goo, gah gah." Chase babbled like a baby.

Leo's eyes went wide. This was not good. Not good at all.

Adam was now two.

Bree's one.

And Chase is a baby!

What a nice way to start a day…

End of Chapter One.