A/N: Hi everyone! I came up with this story idea a little while ago, but didn't have the time to write it till now.

Some things you should know:

- This is loosely based on the season 2 finale/some of season 3 (2k12 verse); however, there will be differences.

- This 1st chapter is the prologue, loosely based on "The Invasion." Like I said - there will be differences.

- This chapter may not be so sad... but I think the next ones will be. Just warning you.

Alright, here we go!

They had been preparing for the invasion for days, weeks, months, now.

It was going to start. Soon.

Leo had carefully organized a plan, which he went over "at least five bajillion times," according to Mikey.

But he had to. He had to make sure everyone knew what to do, when to do it, to prevent anything from going wrong.

He'd had this weird feeling ever since they found out about the Kraang's plan for an invasion. Like something bad was going to happen. So he had tried his best, planning carefully, to ensure that nothing went wrong.

He couldn't afford to lose anything.

Especially not his family.

So that's why he and his brothers and Sensei were gathered in the dojo as he narrated the plan another time.

Leo cleared his throat, facing his family. "As you all know, the invasion is going to start soon. Really soon. In 5 hours."

"In 4 hours and 58 minutes and 23 seconds, to be exact," Donnie corrected.

Leo opened his mouth to say that the remark wasn't needed, but decided against it. It wasn't worth it, considering what was to come.

Instead he said, "Um, yeah. Like Donnie said. Anyway, we all have to stay together and be prepared for anything. We've planned enough, but anything could ruin it."

Leo realized he'd been pacing around the room - a bad habit he had, its cause being worry and anxiety - and stopped, turning to face his family again. To the red clad turtle, he said, "Raph - you and I will be in the front lines, fighting." The hothead nodded rapidly. He was quite excited to bash some Kraang drones.

Looking at the genius, Leo continued, "Donnie - you're our tech person. You'll fight with us, but if we need it, you'll prepare the weapons and missiles and all that good stuff to launch. And if something goes wrong, you'll bring the Shellraiser so we can escape." Donnie nodded. He was proud of himself for doing so many things in such a short amount of time - making missiles, making smoke bombs, adding cool upgrades to the turtles' weapons and T-Phones, and of course, adding cool features to the Shellraiser, like hidden cameras and bullet launchers and paint ball guns and -

"Mikey, you'll be fighting with us, but if Don's busy with his tech stuff, you'll be watching Donnie's back." The orange clad turtle bobbed his head up and down. He knew how important this mission was, because Leo was more serious than ever and because of how long they'd been preparing for it. He wasn't going to fail his brothers by falling for a stupid trap or something.

"Sensei will be watching the lair, and he'll come to us if the need arises. Right, Sensei?"

Master Splinter nodded. "Yes, my son. If you need me, I will be there as soon as possible."

Raph, Donnie, and Mikey waited to be dismissed. The plan usually ended sometime around this part.

They were surprised by some additions.

"And if one of us gets hurt, we escape. Immediately."

Donnie and Mikey nodded in understanding, but Raph frowned. He was going to object, but Master Splinter stood up.

"My sons, I have full faith in you that you will all come out of this mission successful. Remember to stay together at all times. If your leader changes the plan, you will abide to it."

The turtles nodded respectfully.

"Remember...I love you all," their master added softly, and enveloped them in a hug.

"We love you too," they said unanimously, hugging back.

After a few tender moments (...possibly last moments...), they let go of each other.

"Leonardo, I would like to talk to you privately. The rest of you are dismissed."

The other turtles bowed to their sensei and walked out, leaving their father and eldest brother alone in the dojo.

"Leonardo, I trust you to watch over your brothers and protect them at all costs."

"Yes, Sensei."

"You realize that includes sacrifices..."

Leo kept quiet. He knew what his father was going to say.

"...such as the taking of your own life."

The blue clad turtle swallowed. "Y-yes, Sensei."

He didn't want to think about it, but it was inevitable. If he had to die for his brothers, then he'd do it without a second thought.

That was what an honorable leader did.

"I love you, Leonardo, and I have faith that you will make the right decisions."

"I-I love you too, Sensei," the eldest replied.

They embraced.

Master Splinter let go of his son for a few moments, then placed a comforting hand on the turtle's shoulder. He looked into Leonardo's dark blue eyes, eyes filled with fear and sadness, but there was also a bright spark of determination. "I believe you have some final preparations before you leave?"

Leo nodded. "Yes, Sensei."

"You are dismissed to do so."

Master Splinter took his hand off of his eldest son's shoulder.

Leo bowed respectfully before leaving the dojo.

As soon as he walked out, Leo was met with a pair of hands gripping his shoulders, forcing him to turn around and face his immediate younger brother.

"Excuse me, Leo? If someone gets hurt, we escape? Right away? Like a bunch of cowards?"

Leo nodded calmly. "It's the safest option, Raph. We can't afford to have more of us hurt or possibly killed."

"But if we let the enemy go, they could come after us and hurt us even more!"

"Raph... if they hurt us, that means that they're too strong for us. We wouldn't be able to take them down without getting hurt more. Running away sounds cowardly, but it's the safest option," Leo softly tried to explain to his brother.

"If we run away, they'll come after us and hurt us more! We have to try to knock 'em out, or at least, restrain them!"

"Raph-" Leo started.

"Don't 'Raph' me! You just make plans go your way, without ever even listening to my input!"

Leo tried to say something, but Raph wouldn't let him.

"'Cause ya think you're such a great leader, huh? Such a perfect, fearless leader?"

Leo stood in shock, his mouth agape. "Raph, I-"

"Well, lemme tell ya something: you're not! You're a terrible leader!"

"Raph..." Leo said, but the red clad turtle had already disappeared.

The leader stood in shock. Was it true? Was he a terrible leader? He thought his plans were flawless...

...but maybe they weren't.

Maybe Raph was right.

He was a failure. That's why none of their missions went right. That's why Kirby got mutated; that's why the Foot was still intact; that's why the Kraang were starting an invasion.

"I'm sorry," Leo whispered, but no one heard him.

No one saw his tears that threatened to fall, the tears he'd been holding back for long, and then they did fall, like a dam burst open.

No one saw him quietly slip out of the lair, unknowingly leaving his T-Phone and only way of communication behind, and make his way to the surface, where he thought he'd find some peace.

No one knew where he was when the 4 hours, 58 minutes, and 23 seconds turned to 0 hours, 0 minutes, and 0 seconds till the start of the invasion.

5 hours later...

Raph, Donnie, and Mikey were at April's apartment, hoping for Leo to show up.

They had tried to fight as many Kraang droids as they could, when the Foot showed up out of nowhere. It turned out that the Kraang and the Foot were allies, had been for a good year or so.

Though the three turtles had put up a good fight, they couldn't fight as well without Leo, and sustained many injuries. Raph had a cut in his plastron; Donnie's foot was bleeding; Mikey's arm was aching and possibly broken.

And so they had to flee. The sewers had been destroyed, with no sign of Master Splinter, so they went to April's apartment.

Raph choked down a sob. It was all his fault.

His brothers and Master Splinter wondered where Leo had gone, but Raph was too embarrassed and ashamed to say that he'd gotten into a stupid fight with Leo - again - which caused him to run off. And now no one knew where he was or if he was okay.

I'm sorry, he thought. But he knew it was too late.

He hadn't realized the pain he had inflicted onto his older brother till he realized that he was gone, his T-Phone lying on his bed.

Leo could be fighting and in need of help. He could be captured by the Foot or the Kraang. He could be injured or even dead, for all they knew.

Oh, shell, what have I done?

He felt a warm hand on his shoulder and tried to shake it off, but the hand stayed.

Raph turned around and saw Mikey.

The orange clad turtle said softly, "Bro, it's gonna be alrig-"

He was interrupted by the sounds of glass breaking and shattering. Both turtles looked up and saw that something had been thrown into the living room through the window, which was now broken.

Everyone rushed to the object that had been thrown inside.

It was an unconscious, blue banded turtle lying on his black, his face contorted into an expression of pain, his body covered with innumerable cuts and injuries.

"LEO!"

WHAT HAVE I DONE?

A/N: Whew, that was INTENSE! Hope you liked it!

The next chapter will flash forward to a little later. The turtles and their friends will be at April's farmhouse. That's all I'm going to say for now.

Remember to review, follow, and favorite! :)