Now before anyone reads this any further, there will be spoilers to the crossover episode 'Trans-Dimensional Turtles' since this one-shot is set in it, along with some added info to go along with my own TMNT crossover story.
In the 1987 Dimension, the four local Turtles are in their lair living room looking very uneasy.
"AGH! I CAN'T TAKE IT ANYMORE!" shouts Raph87, "Krang is out there getting ready to destroy not just our Dimension, but also the Square guys, whom we were told to NEVER see again until they remember everything!"
"I know how you feel Raphael, really, but what can we do? Even if we did manage to find a way to get them to work with us despite NOT remembering us, we can't made them go sidetrack from whatever adventure they're on right now." Leo87 said, referring to the one notification on Don87's computer about the 2012 Turtles having an adventure right now.
"Michelangelo, did you mess with my computer by any chance recently?" asks Don87 all of a sudden.
"No dude," Mike87 replies, "I wasn't even near your computer at all!"
"Then why is my computer showing a signal coming from outer space?" mumbles Don87, but it's still loud enough for Leo87, who's the closest, to hear.
"What do you mean Donatello?" Leo87 asks, getting the other two Turtles attention.
"Well, see for yourself," Don87 moves out of the way so that his brothers can see what's on the screen.
"What the- did any of the others accidentally got transported into space of those Square guys Dimension?" asks Raph87 upon noticing two of blue, red, purple, and orange dots each in the 2012 Dimension, with one of each color being on Earth and another in space.
"I thought so too," said Don87 "but there hasn't been any readings of a portal to their Dimension opening up since the Square guys Aniki's secretly visited them in their sleep after facing their worse fears thanks to that giant mutant mushroom fungus." (AN: The first time any of them had traveled to their Dimension after that was during another one-shot titled "TF – MONB, A Mutation Day Recovery", where said visit was also mentioned)
"So, the one's in space are posers of the Turtles we met back them or something?" asks Raph87 in slight annoyance.
"If that's true, then why do they have the signal of the amulet piece the Square dudes have?" asks Mike87.
"Michelangelo's right," said Don87, "There are only five pieces of each of our amulet, so the only signal I could pick up are the five of us that have the piece. Those Turtles in space are still the Square Turtles we know, its just there must be an explanation as to why there are two of them."
"We can figure that out later," said Leo87, "right now we need to focus on stopping Krang or else two of the five Dimensions with the amulet pieces are destroyed before it's time. And no matter what, they're STILL the same brothers we know on that month, Raphael."
"Fine," sighs Raph87 in frustration, "not like I have a choice anyway."
"Donatello, can you teleport the Turtles in space over to our Dimension so that we can have an easier time explaining the situation to them without the ones on Earth possibly finding us?" asks Leo87.
"I've never had to teleport anything beyond Earth, let alone that distance from another Dimension," said Don87 before concluding, "but I can try."
"Since we're not sure if they know we were there during that month with them, we'd better pretend like we didn't know anything about them, their Dimension, and even as if we had never traveled to their Dimension before, just in case we have to chase after Krang there instead of here," instructs Leo87, "Plus, whatever you do, don't mention to them ANYTHING about the month unless they ask for themselves."
The other three Turtles nod in understanding before leaving the lair to get to work.
/ (Later, in the 2012 Dimension,)
After managing to disarm one of the Dimensionalizer on top of Channel 6 building, the two Turtle groups arrived at the 2012 lair, with the 1987 Turtles staying outside thanks to Raph12's silent threat to them. But upon hearing that Dimension's Master Splinter stating the 2012 Turtles had only just left the lair to patrol the city, the 1987 Turtles couldn't help but look at what's going on.
"I wonder what does Leo meant?" whispers Leo87, unaware that he's moving next to Leo12 until Master Splinter notices him.
Instantly upon noticing this, Raph87, Don87, and Mike87 starts moving around the lair like they've never been there before just like they promised each other they would. Splinter demands to be told what's going on and asks Don12 to explain.
"Yeah, um, they were transported here from an alternate dimension sensei, along with this weapon we have to defuse," explains Don12, grabbing Don87 before quickly backing away towards the lab, "like ASAP."
Once the Donatello's are safely in the lab, Don12 lets go of Don87 and sighs in relief, "Phew, I know I really want to see sensei again, but not with him being so strict."
"What do you mean by that?" asks Don87 in confusion.
At that moment, Don12 immediately regret saying what he said so loud since he completely forgot Don87's in the lab along with him.
"Um, shouldn't we be focusing on defusing this thing?" Don12 asks, quickly head towards his computer and starts working. After a while, the Square Turtle notices his counterpart in the room is still standing at the same spot, "Aren't you going to help me out here?"
Don87 sighs before helping Don12 out and admitting, "Sorry it's just, I'm confused as to who you guys truly are. I mean I know you are this Dimension's Turtles, but are you…"
"The same ones you guys met during that month?" Don12 guessed.
"H-How did you know?" gasps Don87.
But before Don12 could say anything, the computer picks up some sort of signal while disarming the Dimensionalizer along with some results. The two Donatello's look at the screen and
The two Donatello's are disabling the Dimensionalizer in the 1987 Dimension, just as another portal opens up.
"They're almost here," warns Don87 as he and Don12 arrives and immediately get to work.
"Almost," Don12 concentrates before the Dimensionalizer is deactivated, "We did it! Two Dimensionalizers down!"
"No matter," said Krang, "There's still one left in the Primary Turtle reality. If those Turtles are destroyed, then so are all of you!"
'Looks like he still remembers what happened the last time it happened,' realizes Don87, 'only this time, Krang doesn't care about the consequences like the Utrom Shredder!'
"Donnie's, get to the third reality!" orders Leo12.
Don87 quickly set the Portal Projector towards Turtle Prime's exact time and place of the final Dimensionalizer, which he guessed must be when the Primes he knew on that month were the same age as when they first met before then.
"There!" Don87 sets the coordinates and opens up a portal that he and Don12 quickly jumps through.
Upon arriving Turtle Prime, Don87 immediately said, "What kind of Dimension is this?" in shock since he's still pretending to not know any of the Turtle groups he teamed up with in that month towards Don12.
After deactivating the final Dimensionalizer, the two Donnie's return back to the others and quickly gets everyone away, only to end up back in the Technodrome the 1987 Turtles are more familiar with. But despite that, the remote that hacks their Dimensional portal was destroyed and Krang was banished by Sub-Prime for trying to destroy the Dimension their race had been trying to take over for thousands of years.
"Let's take this blob of chewing gum down!" commands Leo12.
"With pleasure," said Leo87 before all eight Turtles attack Sub-Prime.
"Guys, don't hold back," Leo87 secretly commands to his dimensional brothers, with all three of them nodding in agreement.
It was right at that moment, Raph87 notices Raph12 slip and about to be attacked by Sub-Prime. Raph87 got angry and quickly jumps from behind and slices the robot's head off before stabbing it to the ground.
Impressed at the sudden change of fighting style, Raph12 said in awe, "Nice move Raphael!" before Raph87 helps him up.
"I've had enough of this dweeb!" said Leo87 before hearing Leo12 said "Turtle Power!" that made a quick smile form on his face before attacking Sub-Prime.
Unfortunately, his swords got broken during the fight, but Leo12 jumps onto the robot's back and drags Sub-Prime out of it towards the Michelangelo's. The two orange-wearing Turtles use Sub-Prime as a ball to bounce him around before Don12 swats him away with his Bo like a baseball bat, while Mike87 finally said the "Booyakasha!" that he's been holding in during the whole meeting, just when Don87 uses his Portal Projector to send Sub-Prime to Turtle Prime.
"Well that wasn't such a chore now, was it?" jokes Raph87.
The two Leonardo's face each other before Leo12 said, "Leonardo, thanks, for everything."
"No, thank YOU," corrected Leo87, "Without your help, all of our realities would be doomed!"
The two leaders in blue shake hands with one another before Leo12 asks, "All realities as in ours and the other three group of Ninja Turtles my brothers and I met during that month?"
That made Leo87, Raph87 and Mike87 gasp in shock before Don87 jumps in and said, "They know we were with them during that month."
"But how?" asks Leo87, letting go of Leo12's hand, "You guys hadn't met us until today since then."
"We actually had seen you guys once before," said Don12, "and if I remember correctly, it should be around this time in the past."
"In the past?" asks Raph87, before Mike87 also asks, "What do you dudes mean?"
The 2012 Turtles nod their heads with one another before Leo12 said, "We'll tell you guys, but it's quite a long story."
And so the 2012 Turtles explain to the 1987 Turtles about how they're from a future where the Earth got destroyed, with them along with April and Casey being the only survivors, and about the Triceratons along with their adventures in space to try and prevent that future from happening again.
There was a moment of silence before Mike87 asks, "Did you dudes really travel back in time?"
"Yeah we did," confirms Mike12 before taking out a piece of paper and hands it to Don87, "and we got this letter not that long before then."
Don87 reads through the letter and gasps, "This is your handwriting Leonardo!"
"What? Let me see that," Leo87 takes the letter and sure enough he recognizes his handwriting on it as well as something else, "It's not just mine, the other three Leonardo's also wrote this."
"After we read the letter, the scrapbook starts to show silhouettes of Ninja Turtles instead of blurry images we couldn't make out before," said Leo12.
"By the way Mikey, why do you have the letter with you?" asks Raph12.
"Because I wanted to see if re-reading it could help me remember anything else," admits Mike12, "I didn't realize I still had it with me until we were back at the lair."
"Speaking of which, we should be getting back to where we all came from," said Don87, "We weren't supposed to be talking about the month except confirming what you guys already remembered."
"Why do you guys have to keep it a secret from us anyway?" asks Raph12, "I mean, I just don't get it!"
There's a look of hesitation in the 1987 Turtles faces before Raph87 said, "It's because of the amulet pieces we're all guarding."
The 2012 Turtles are a bit confuse as to what Leo87 meant before taking out the strange pendent they've had after the month.
"You mean these?" asks Mike12.
"Yes dude," confirms Mike87.
"Whatever happens to you guys, DON'T lose those pieces!" said Leo87, "They're the very key as to when you'll remember everything of the month again," he then turns towards Leo12 and add, "as well as your fondest childhood with your Aniki."
Leo12 gasps upon hearing this and wants to know more, but before he could say a word however.
"We really want to tell you guys more, but we can't," Leo87 admits sadly.
Despite feeling sad for not knowing more, Leo12 said, "It's fine, we understand."
So Don87 takes his Portal Projector and opens a portal near the 2012 Turtles and said, "I've set the coordinates to take you guys back to the spaceship you guys were on."
"Here's the letter back," Leo87 hands the letter back to Mike12, who just shook his head and gives the letter back to Leo87.
"You dudes should keep it," insists Mike12, "That way you guys have a reminder of what's to come in our Dimension, as well as how we're going to save the Earth."
Leo87 keeps the letter away before the two Turtle groups look at one another one last time, bowing towards one another before Leo12 said, "Come on ninjas, let's go home," and the 2012 Turtles enter the portal.
"Good luck you guys," Leo87 said before joining his brothers to return to their own Dimension.
After getting a box of pizza, Leo87 asks, "Do you think they can do it?"
"I'm sure they will dude," reassures Mike87.
"Yeah, plus they did already stop the Triceratons from having one of the pieces, with only one more left," said Raph87.
"But whether they could change the future is something we should worry about later," said Don87 before the four of them tale a slice of pizza, "For now, it feels great to be back home."
That's when a giant Kraang worm appears attacking the city. But just as they're trying to stop the worm, a sword pierced through it from the inside and cuts it open, much to the 1987 Turtles shock.
"What the-?" Raph87 gasps.
"Whoa!" said Leo87.
That's when a roar is heard coming from inside the worm before a Tiger mutant appears out of it.
"Um, I think things just got really bad bros," said Mike87 before the four of them attacks the Tiger mutant.
"Easy Raphael," Don87 said, helping Raph87 head towards the lab since he's the most injured out of the four of them during the fight against the Tiger mutant.
"Um guys," Leo87 calls from where he and Mike87 are sitting near the computer, "you might want to hear this."
"I wonder how the pudgy guys will react when they know the square ones saw them without them knowing?" asked Leo03 in the monitor.
"Wait, they actually saw us?!"Don87 said, pretending to be surprised by the news.
"Major bummer dude, not only do we miss one of their adventures, but that they saw us too," Mike87 said, also playing along.
"When did you guys get back?" asked MikePrime.
"Just now," replied Raph87, "we were just heading to Donatello's lab to patch our wounds we got from fighting a freaky worm earlier today when we discovered the signal that the square ones just had an adventure."
'Along with our injuries we got from fighting alongside the Square guys that came from the future,' added Raph87 in his mind.
After cutting off the communication with the other Turtle groups, Don87 said, "We can't tell them about our own adventure with them until the time they said the Triceratons are going to invade Earth."
"Great, now we have to keep secrets from them too?" asks Raph87.
"I hated keeping secrets from the Square dudes," admits Mike87, "I'm not sure fi I can do the same with the rest."
"It's going to be tough on us sure," said Leo87, "but we have to hope that the Square Turtles will make their Earth's destruction a distant memory instead of a permanent reality."