Author's Note: Thanks for your reviews! And don't worry about the turtles getting into trouble. Why should they? It's only a fanfic written by one crazy author… Oh wait.

About 2012 April and Donnie. In the 2012 show, if it was obvious that both Donnie and Casey were in love with April, it remained unclear whether she was in love with any or both of them. Most of the time, she acted towards Donnie like a close friend who didn't know how to react to his unwelcome feelings but didn't want to see him suffer. The issue was never resolved and won't be in this fanfic. You can absolutely imagine that at some point she will choose Donnie.

And now, the next chapter!

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United We Stand, Part 4

~2012 Leo~

I watched Leonardo and Donatello, every sense on alert. What was this danger they were talking about? Did it threaten the safety of my family?

Leonardo sighed. He was standing slightly behind Donatello, a hand on his shoulder, and looked warily at me.

"I hate to be the bearer of bad news, but enemies are after us. We had a head start on them, but now…"

He didn't finish his sentence, but he didn't need to. I could do it myself. Now they couldn't dimension-travel until Donatello figured out something to replace or repair their crystal.

Which meant their enemies, whatever they could be, would sooner or later arrive in our dimension.

Donatello himself had drawn features and seemed crushed under a heavy weight. My gaze softened at the sight of his bloody forearms. They had mentioned earlier that reloading their crystal would take a few hours, and none of them had seemed concerned about it. Whoever these enemies might be, they weren't about to crash in our dimension right now.

First things first.

"The bathroom is right there," I pointed. "The first-aid kit is under the sink. When you're done, we can talk about these enemies and how we can fight them."

Leonardo courteously nodded his appreciation, and I left the two of them, my mind spinning.

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I stopped by the kitchen, where Mikey was massaging Donnie's neck and shoulders while my purple-clad brother was forlornly licking five scoops of ice cream on top of a giant cone.

Mikey never does things by half when it comes to cheering us up.

"Hey, Donnie. You okay?" I asked softly, taking a stool next to him.

My genius brother nodded determinedly.

"Yes. I have determined by now that I overreacted. It is probably due to the emotional impact of the vision of Casey and April exchanging a languorous engagement kiss that popped into my mind. It probably was at sunset in a beautiful flowery garden, and they were embracing, and…"

I coughed, embarrassed by the image that was now forming in my own mind.

"I get the picture."

"Donniiiie," Mikey moaned. "Stop brooding and eat your delicious ice cream."

Donnie obediently took another lick while I watched his ice cream suspiciously. One of the scoops had a really strange color and texture…

"Is it… pizza ice cream?" I asked, bemused.

Mikey nodded emphatically.

"Pizza ice cream is the best, bro."

Donnie didn't protest, which was either in agreement or because he felt too down to do so. I shook my head, determined not to share my opinion on the matter with my enthusiastic orange-clad brother.

"So, uh… What do you think of our guests so far?" I asked.

Mikey grinned.

"They're so cool! They remind me of the other us we meet, remember? Except these ones are much taller. And serious. I would love to learn more about them, that's a pity they're leaving so soon!"

"Or not," Donnie muttered, still clearly shell-shocked. "Their universe is all wrong anyways."

I bit my lip.

"Yeah, about that… They'll probably stay a while longer now."

Mikey turned to look me in the eye, curious and a little hopeful.

"Really? Why?"

"Well, I don't know how it happened exactly, but Donatello's crystal shattered. Right now, they can't go home."

"Really? That's awesome!" Mikey exclaimed, before assuming a thinking pose. I raised an eye ridge and patiently waited for him to amend his statement. "Except, you know, they are now lost in a different dimension for who knows how long. Away from their friends and family. Uh… Not so awesome in the end."

"Indeed, Mikey."

Donnie finished his pizza scoop and got started on the next one.

"So that's what the whistling was all about. Hmm. That's not good."

My concern about him grew by the second. He had heard that something weird was happening in his beloved lab and he hadn't run to check it out? It wasn't like him.

"It's such a shame, it was a very beautiful crystal," he added absent-mindedly.

"Well, maybe you can repair it," Mikey said in a soothing tone, still massaging Donnie's shoulders.

I took a deep breath.

"There is something else. They are being followed by an unknown enemy."

This time, I had the full attention of both my brothers.

"What kind of enemy?" Donnie asked, his eyes narrowing.

"I don't know yet. Let's meet in the dojo when you'll be finished here. At the moment, Leonardo is helping Donatello with the cuts he sustained when the crystal exploded."

Mikey grimaced at the thought.

"Got it, bro," he nodded. "We'll be right there."

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Next, I walked to the lab where Raph, Michelangelo and Raphael were still trying to pick up the crystal pieces. I wondered idly if Michelangelo really intended to put them back together.

I had done my best to hide my renewed anxiety and I was pretty sure it didn't show on my face, but Raph must have felt it somehow, because he took one glance at me and narrowed his eyes.

"What's the matter, Leo?" He asked, crossing his arms and clearly challenging me to deny something was wrong.

As if I intended to do such a thing. I tried to feel offended, but I didn't quite manage to.

After all, I haven't exactly a clean record in that particular department.

"Leonardo told me that they are being followed," I answered. "He hoped that they would be gone before it would become a problem for us, but it didn't turn out that way."

Raph huffed.

"Oh really? Wonderful," he muttered.

I repressed a smile. I knew he was secretly rejoicing to have an enemy to fight. Typical Raph.

Raphael and Michelangelo exchanged an uneasy glance.

"Yeah," Michelangelo added. "Sorry for getting you into trouble with us. It was never the plan."

Raphael said nothing, but he looked skeptically at Raph and me. And was there a hint of concern in his eyes?

Anyways, Raph bristled under his gaze and I shook my head before he could speak.

"Things rarely go according to plans. I'll be in the dojo. Please join me there when Leonardo and Donatello will be back. We need to talk about what comes next."

"Sure, Leo," Michelangelo answered hesitantly. "No problem."

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I knew I only had a few minutes before everyone gathered in the dojo for something that was beginning to resemble a war meeting, but I still took the time to bow respectfully to my father's shrine before sitting cross-legged in front of the dojo tree, closing my eyes to try gathering my thoughts.

Despite what Michelangelo had said, I could foresee many a problem.

The fact that we knew very few about each other, to begin with – Donnie's reaction to the news of the other April and Casey getting married was proof enough of that, along with Donatello's loss of control when Raph had mentioned that April had torn Donnie apart once – I had to remember to tell him the full story, so Donatello wouldn't think lower of her because of it.

Or the fact that our four guests were tiptoeing around me, clearly unsure of how to behave.

I couldn't forget their shocked expressions when they had understood that our father was dead and I was Sensei. Clearly, they still had their Master Splinter.

What was worse, I didn't think they took me seriously.

I suppose it didn't help that I was watching Space Heroes with Mikey when they arrived, I thought wryly.

Oh well. That couldn't be helped, and if they couldn't see the sheer awesomeness of that cartoon – Raphael's disgusted look hadn't escaped my notice - then the loss was all theirs.

They probably thought I was too young and unexperienced to be leading our clan. I couldn't blame them. I personally thought the same…

A light breeze made me open my eyes. Next to his shrine, my father's ghost was smiling fondly at me.

"Father," I whispered in a hoarse voice. "What am I supposed to do now?"

"Leo?" Michelangelo's voice suddenly resonated in the dojo. It was uneasy, as if he feared to disturb me.

I could feel the four taller turtles' presence on the dojo doorstep, with my own brothers close behind. I nonetheless took a few seconds to turn towards them, knowing that Splinter's ghostly form would disappear as soon as I would take my eyes off him.

"Come in," I finally said, my determination renewed. "And make yourself comfortable. We have a lot to talk about."

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"Wait a minute," Donnie exclaimed, squinting in our counterparts' direction. "What do you mean, you don't know who these enemies are?"

Leonardo, Michelangelo, Donatello and Raphael exchanged uneasy glances. We were all sitting in a circle. My own brothers were on my right and our guests on my left, with Leonardo next to me. I couldn't help admiring his perfect lotus position. Raphael was sitting next to Leonardo, arms crossed, while Raph was to my immediate right, his arms crossed too. A detached part of me – the part that wasn't trying to figure out what the heck was going to befall my family - was finding this immensely funny.

Next to Raphael, Donatello was leaning forward, moving his hands quietly while explaining what he knew about their mysterious pursuers. His arms were wrapped up from wrist to shoulder. Next to Raph, Donnie had his elbows on his knees and leaned his head on his hands. Completing our circle, Mikey and Michelangelo had chosen to sit next to each other and were constantly swinging back and forth, apparently both unwilling to stay still.

At least I don't have to worry about these two getting along.

"We don't know where they come from," Donatello corrected. "They have been chasing us across dimensions ever since we've found and used this crystal. We've already had one direct confrontation with them, and it didn't go well."

"But who are they?" Raph insisted.

"That's a good question," Michelangelo nodded vigorously. "A very good question. And I would really like to know the answer myself. But they were cloaked all the time. All I know is that they fight really, really well. Ninja style."

He exchanged a quick glance with Leonardo, and I narrowed my eyes. What weren't they telling us?

Raph bumped his right fist against his left palm.

"Well, we fight really, really well too," he exclaimed derisively. "We can help you big guys beat these losers, as you obviously didn't manage to do so yourselves."

Raphael clenched his fists.

"You don't know what you're talking about," he said through gritted teeth.

"What makes you think that you will be more able to fight them once you're back in your own dimension?" I interrupted, suspicious but unwilling to let things escalate. I knew far too well that Raph had a short temper, and if Raphael did too…

Well. Better not to think about it. I had enough on my plate right now.

"We have allies that could help us," Leonardo answered cryptically. "Allies that are used to deal with… mystical… situations."

I raised my eye ridges.

"Mystical."

"Yes," Leonardo went on, looking at me intensely. As if he was gauging me. "The reason why we couldn't beat them the first time is that they have mystical weapons."

Something in the way he had said that last sentence unsettled me.

"Do you, by any chance, happen to know these weapons?" I asked quietly on one throw of the dice.

Leonardo tilted his head. Next to him, Raphael looked at me in obvious surprise. I would have liked to see the others' expressions, but I wasn't going to look away from Leonardo now.

Was I having a staring contest with my counterpart from another universe?

Yes. I guess I was.

Whatever.

"Yes," Leonardo answered reluctantly. "It's a long story."

"You'll have to tell us more," I replied softly but determinedly. "We need to be prepared for them."

Now everyone else was holding their breath. Leonardo was still looking at me as if he wasn't sure how much he could trust me with.

"Soon, we will stand side by side against these enemies of yours," I insisted, holding his gaze. "Everything you hide from us now will work in their favor later."

Something in Leonardo's gaze softened.

"You don't have to," he whispered. "We could lead them away from you."

I heard Raph snort, but he didn't retort, trusting me to talk for all of us.

"This is our universe," I replied slowly, enunciating every word. "You're not in this alone, not when you all but crashed inside our lair. We'll do everything we can to help you. But you have to trust us."

Ever so slowly, so reluctantly, Leonardo nodded. But he did, and I held back a sigh of relief. Now we were going somewhere.

My counterpart took a deep breath and purposely detached his gaze from mine so it could embrace the whole assembly.

"Then let me tell you the story of our time with the Ninja Tribunal."