AN: I started writing this before finishing season 3, so the mechanics of the Hare/Rabbit Miraculous I use are different from the series. But the series leaves all kinds of plot holes and confusion with their version of time travel, so I'm okay with not copying them! If you want a better explanation, I wrote a 500-word tirade on the subject that I'd be happy to send you…
To Rose Tiger: Oh, don't worry. He will…
To The Keeper of Worlds: You're close. Mylène is Multiplice (Mouse Miraculous); "She-Goat" (Goat Miraculous) is Juleka. And Rose is "Piglet" (Pig Miraculous). If/when those two receive miraculous for real, I'll come up with better hero names for them!
Before getting into the story, I would like to apologize in advance to my readers in Portugal…
"Oh, $#!t! This… this looks bad, Queen Bee. You need to get there now!"
"What about King Monkey and De Gaulle? Shouldn't I wait for the rest of the team?"
"I-I don't think you need to worry about that. I'm watching the satellite feed from headquarters and it's… gone."
"What do you mean, 'gone'? You mean the boat's gone?"
"I mean Portugal's gone! There was a massive release of Miraculous magic, then there was another, and then a third at least three levels of magnitude greater than the first two. I-I can't contact anyone on the ground there – not our friends, not EMS, not anyone. I don't see Viperion, She-Goat, or Piglet anywhere – wait I-I think I see something black down there. I'm zooming in, and I can definitely see someone in black and he's…" Pegasus' voice dropped "he's kneeling over something that looks like a body. I'm opening the portal."
A swirling portal appeared in front of Queen Bee in her apartment. She stepped through it without hesitation. She blinked and lifted her hand to shade her eyes from the bright sunlight. Looking around, she saw that she was near the bottom of a long, wide, deep depression. Her first thought was that an alien giant had scooped out a huge chunk of the continent with an ice cream scoop. And right in the middle of the depression, Queen Bee could see a prone form dressed all in black, kneeling. She could just make out his shoulders quivering.
Queen Bee slowly walked over to the kneeling figure. "Cat?" she began hesitantly, reaching out a hand to touch his shoulder, only to withdraw it a moment later. "Cat Noir?"
"I tried Miraculous Ladybug, and it didn't bring her back," he said, so close to a whisper that Queen Bee had to strain to hear his words. "I tried combining the miraculous, and it didn't bring her back." He suddenly looked up at Queen Bee, anguish and accusation etched into every line of his face. "Why won't it bring her back?"
Queen Bee de-transformed and knelt next to Cat Noir, pulling him into a hug. Looking closer, Chloe could see that his suit was actually covered with red splotches in a checkerboard pattern. Examining his face, she saw earrings jammed into earring holes she knew he had not had when she'd last seen him the day before. "Cat, what did you do?" she asked urgently.
"I told you, I combined the miraculous to bring her back. But it didn't work!"
Chloe looked down at the ground in front of them, and her breath caught in her throat. There, lying on her back in a still-expanding pool of blood, was Marinette. A stab wound ran across her chest and nearly bisected her body, and her eyes were still staring forward into the sky, but without seeing. Her mouth was open in an expression of shock.
Chloe squeezed Cat Noir tighter against her chest and whispered, "What happened here? What happened to Marinette?"
"They killed her. So I killed them. And now I am Cat Bug Noir."
Present Day
"It took another hour to get Adrien off the ground and convince him to let the paramedics take Marinette's body for transport back to Paris. When King Monkey and De Gaulle–"
"'De Gaulle'?" Marinette asked.
"We never really got his full story," Chloe explained, shrugging. "He claimed to be the great-grandson of Charles De Gaulle, but we never confirmed that. He didn't have any powers, but he could get just about any tool you might need. And you did not want to fight him hand-to-hand."
"Anyways, what happened next?" Adrien prompted, giving Marinette a look.
"When King Monkey and De Gaulle arrived, I nearly had to tackle Adrien to the ground so he wouldn't attack them," Chloe answered with a shudder. "KM and I nearly took the miraculous from him right then and there, but we thought he was just grieving, that he would recover in time. So we let him be, and we missed our chance to spare the world.
"Adrien was my best friend growing up, and I tried to comfort him as best I could after it happened, but he withdrew into himself. It was almost like he became a different person without you around to brighten his life. I'd known how special you were to him for years, Mar – it's why I made it my personal mission to get you back together after last week's breakup. Without you… without the family you were starting… I guess he decided his life just wasn't worth living anymore.
"Daddy insisted on hosting a huge state funeral a week later for Paris' fallen hero, complete with bands, a full honor guard, all the works. All the Heroes of Europe and delegations from every other hero group on the planet came to pay their respects to Earth's Greatest Hero, complete with a flyover from the Space Defense Force. Finally it was time to fold the flag and bury her beside the Arc de Triomphe. Taureau Dechaine and King Monkey did the honors of folding the flag before handing it to Cat Bug Noir, who hadn't de-transformed since her death.
"But when Taureau Dechaine went to hand the flag to Cat Bug Noir, he took one look at him and punched him in the chin so hard it snapped his neck and he flew through a dozen buildings. His body didn't stop until it slammed to the ground on the bank of the Seine and bounced into the river. Then Cat Bug Noir turned on the rest of us. 'You all think you knew her? That you loved her? Where were you when she died? Where were you when we got called out to stop those monsters on our anniversary? I'm sick of the hypocrisy, sick of the falsehood, sick of the false friends! And I'm sick of you!'"
Chloe stopped. Some days this horror felt like ancient history, yet on days like today it still felt like it only happened yesterday. She closed her eyes for a moment before she continued. "Alya gave me a look of fear that shifted instantly to determination before blowing on her flute. Cat Bug Noir took one look around himself before shaking his head, reaching out, grabbing the flute out of her hands, and crushing it in his fist. He extended his staff to strike her, but Nino pulled her back behind himself, raised his shield, and used Shell-ter to form a barrier over them. Cat Bug Noir struck the Shell-ter over and over, harder and harder, with his staff, but it would not budge. Finally he jumped on top of the Shell-ter, leapt into the air, and shouted 'Cataclysm' before driving his staff like a spear into the Shell-ter. The staff shattered the Shell-ter, slammed through Nino's shield, broke his miraculous, and finally expended its Cataclysm energy on Nino himself, who turned to dust with his arm still around Alya, trying desperately to keep her safe. Alya was run through with the staff in the same strike and fell to the ground, dead. A little residual Cataclysm energy released on her miraculous, destroying it.
"By this time I had finally shaken free of my horror enough to use Venom. I threw my top at Cat Bug Noir at the same time that King Monkey threw a clothes hanger from the opposite direction. Cat Bug Noir evaded both attacks, and King Monkey's Uproar disrupted my powers just before my top would have paralyzed him. With my powers temporarily gone, I panicked. I picked up my daughter, Ana, who was standing right next to me, and ran for my life, my dying friends' screams echoing in my ears. That was the worst hero slaughter we had ever experienced, worse even than the invasion. Cat Bug Noir murdered almost all the Heroes of Europe that day, alongside half the visitors."
Chloe looked around the table at the twin expressions of shock and horror on her companions' faces. She sighed. "I am sorry to have to tell you this. But you must know what happened if you are going to help me fix my mistakes and stop him."
"But what can we do?" Marinette asked, swallowing hard.
"Only the Ladybug and Cat Miraculous are powerful enough to counter a holder of both the Ladybug and Cat Miraculous," Chloe told them. "Many other miraculous holders tried to fight Cat Bug Noir, even together. But even Soaring Eagle and Grey Wolf, the holders of the American eagle and wolf miraculous, working together with Joey, the Australian kangaroo miraculous holder, and Roaring Lion and the Great Scarab, Africa's lion and scarab miraculous holders – even the five other most powerful miraculous, the most powerful of the three other miraculous sets. Even they together could not stop Cat Bug Noir. All five of them were killed at one time, and Cat Bug Noir claimed all their miraculous and added them to his own collection."
"And you want us to do what all of these people couldn't do?" Adrien demanded, wide-eyed.
"In a word, yes." Chloe nodded. "You are my only hope."
"What do you expect from us?"
"After the funeral, I went into hiding with Sabrina, Max, a few other heroes who survived the Purge. I had to keep Ana safe. We had to stay underground, keep moving so Cat Bug Noir's spies and shock troopers couldn't find us. He's been trying to collect all the world's miraculous for a decade, hoping that combining all their power might bring Marinette back. It was only a couple years ago that I was able to break into Cat Bug Noir's lair – our old headquarters under his – well, your – mansion. We opened a portal into the lair, and I grabbed what I could: the box with most of Cat Bug Noir's miraculous collection and the Book of the Miraculous. Of course, he put a magical barrier around the lair to prevent any more portals as soon as we'd escaped." Chloe fell silent for a moment, fighting back the tears that threatened to fall. She hardened her gaze and continued, "It took a while for Max to decode the Book, but we figured out that only another set of Ladybug and Cat Miraculous could balance out a pair being bent to evil purposes. That's why I'm here. Simply put, I need you to stop Cat Bug Noir before he throws my universe so far out of balance that not even the miraculous can put it right again."
"And this is our future?" Adrien whispered, looking over at Marinette furtively with a pained expression on his face, which was rapidly turning green.
Chloe noticed the look and gave him a sad smile. "Not exactly," she explained. "Do you understand how the Hare Miraculous works?"
"You can travel forward and backward in time as far as you want in either direction," Marinette answered.
"That's one way of looking at it," Chloe said, nodding. "I used the miraculous to go back to a time before my younger counterpart set you up on this stupid date. However, nothing I do here alters my own past. Do you see? I walked past you while you were coming into this coffee shop, something that I do not remember happening on that day. My presence here has not changed the way things happened on this day 20 years ago in my own timeline. So I could pull out a gun and shoot you right here and now, and the events of my own timeline will still have taken place exactly the way I remember them. But I would have altered your future by doing so."
"So the Hare Miraculous isn't exactly causing you to travel through your own timeline," Marinette said, eyes brightening in understanding. "You're actually traveling to different versions of the timeline."
"Gold star for you, sweetie," Chloe said, smiling. "Think of the Hare Miraculous as transporting you to different dimensions, or alternate realities, or something like that. If you want to strictly alter events within your own timeline, you use the snake miraculous. And the horse miraculous strictly transports you through space within the same time and dimension. So now you understand what that means, right?"
Adrien smiled in relief. "It means that whatever happened in your timeline won't happen in ours."
"Almost," Chloe told him, grimacing. "Simply because I'm here, it won't happen the same way, but the big things could still happen in a similar manner. The aliens could still invade in 2024, you could still marry in 2026, Mar could still be killed in 2028, you could still threaten the balance of the universe in 2039. All of that stuff could happen, but it doesn't have to happen. Your future is not fixed. But my past is. So will you help me save my present?"
Adrien and Marinette looked at each other across the table for a minute before both nodding simultaneously. "We're in," Adrien said.
AN: Adult future-Pegasus has learned how to open portals from anywhere (within a certain range) to anywhere. In "Startrain" Max opened a portal in front of the train rather than right where he was standing, so it's not much of a stretch to say his range can expand even beyond that. All of the characters are learning to control their abilities in different ways: Adrien discovered that he can channel Cataclysm through his staff in "Milady," and Chloe was able to use Venom at a distance by throwing her top (which turns into the stinger for Venom) in "Mind Games."