A/n: My first attempt at writing a multichapter fic. I hope you guys enjoy it. This story takes place in the third season, post episode, "The Deadly Venom".

Disclaimer: I do not own the Teenage Mutant Ninja Turtles or any of the canon characters that will be used in the story. They all belong to their respective owners.

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Prologue

He blinked in confusion, looking around to see if his mind was playing tricks on him and saw that the dojo was in the same condition it had been before he had closed his eyes to start meditating. From the shadows and position of the sunrays coming through the grate above, it was clear that not much time had passed either.

But...

Leo bit his lip and reached forward to touch the green shoulder of a turtle kneeling in front of him. It could be just a dream but he never had dreams like these. His brothers' voices coming from the pit, discussing the same topics they were discussing before, further proving that this was no dream. It was all too real.

He lowered his hand to fall on the shoulder of the turtle in front of him; A blue-masked, katana wielding, meditating turtle.

It passed right through and Leonardo pulled away from his physical form with a gasp, cobalt eyes widening in astonishment. If he remembered correctly from what his father had told him when he was very young, then he was performing something only a very few martial artists could do and even Master Splinter hadn't mastered yet; Astral projection.

"Wow..."

Leo whispered in awe and stared down at his ghostly fingers, wiggling them for no other reason than shear curiosity at their transparent look. He checked his arms, legs, shell and the rest of his body, which also looked faded and almost transparent.

An image of Mikey's reaction if the youngest had been in his place flashed through his imagination and he chuckled. His baby brother would freak out and have a geek explosion simultaneously, thinking he was dead and had become a ghost. But Leo knew better, not that he wasn't allowed to geek out too.

This was just too awesome!

He looked to the right, at his rat sensei kneeling beside his meditating form, oblivious of what his eldest son was currently doing. The ninja master would be in for a big surprise when Leo told him what he is able to do. No need to disturb him for now, though.

He still had an hour before the meditation session with Splinter ended so Leo decided that he would explore around a bit in this new form, see just what unique abilities one had while performing astral projection. Maybe he could test how far he could wander from his body or even check on his brothers without them knowing.

With those thoughts in mind, he started to walk towards the dojo doors before pausing midstep and gazing at the blinders which had been placed at the open, domed spaces over the pool next to the pit. Well... he was a spirit so maybe he could just... Leo closed his eyes to concentrate and was suddenly launched high up in the air.

"Woah!"

He clenched his eyes shut and when he felt nothing more, slowly opened them to see the dojo mats a few feet below him.

"Phew." He sighed out in relief at seeing that he was just floating, not beamed upwards like a rocket or tossed around senselessly like shopping bag in a hurricane. Just Floating.

The thought repeated itself in his head and Leo straightened himself with a wide grin, staring down at himself.

He was floating! Like a super hero!

Laughing in excitement, he moved to the right instead and flew straight through the blinders and into the pit.

"This. is. Awesome!"

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First stop: Check on Donnie.

Leo was finally finished with his numerous test flights through the lair which he was doing just for fun and had decided to use this form to check up on his younger brothers without them teasing him about being a motherhen.The impossibly wide, excited smile never leaving his features.

He poked his head into the lab through the closed doors and looked around, catching sight of his genius brother working with some of the chemicals and mumbling to himself. Pulling inside the rest of the way, Leo moved right infront of the purple-masked ninja who didn't react in the slightest, completely unable to see him.

"Hey, Donnie. What you up to?"

Obviously the other turtle did not hear him and kept mumbling to himself about 'which analytical process would work the best to recognize the main working agent of the serum and the silica gel seamed appropriate for the process of chromato-' Leo shook his head to stop himself from trying to translate his brother, not understanding most of the words Donnie was saying. He instead focused on the slower than usual movements his brother currently possesed and not on the words he was speaking.

Well, the genius seemed to be fine. Looking tired and overworked but otherwise fine. Leo made a mental note to get Donatello to take a break and rest for a while once he was done with his own meditation.

Finished with the first task, he felt his curiousity taking over once again. What if he touched someone who was conscious? Would they sense him?

Leo stared down at his ghostly hand before looking at his brother. Would Donnie sense him?

Welp, he shrugged, only one way to find out.

He reached forward to grab his younger brother's arm after the turtle had put down the test tube and, predictably, his hand passed right through. He watched carefully for Donatello's reaction and noticed how the younger had shivered at his touch.

"Who lowered the temperature on thermostat?" Donnie mumbled while rubbing a spot on his arm, still feeling the chills; like something cold had touched him.

Leonardo stared on with wide eyes as the purple-masked turtle trudged away to check the thermostat.

Donnie had sensed him. His brother had sensed him.

He gazed down at his ghostly hand once again in fascination. "Cool."

After a whole minute, Donnie walked back to his desk with a confused look on his face which snapped Leo out of his stupor and the invisible turtle decided to go see the other two turtles.

Next stop: Check on the mischievious Mikey.

Speaking of mischievious, the blue-masked spirit noticed that Mikey and Raph's voices had quitened a while ago and they were nowhere to be seen.

Hmmm. Just what were those two up to?

Suspicion filling him, Leo floated right through the lab doors and set out in search of his mischievous brothers.

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A/n: There you go! The first chapter. Let me know what you guys think.

I decided to test the waters with this one before starting the Au fanfic stories with much more interesting plots. I hope you all enjoy it.

And stay tuned for more! Leo is in for some deep, deep trouble.