A/N: This takes place before season 4, as it was thought of before it started to air, so season 4 onward does not take place in this story.

What Was Left Behind

Prologue

Fourteen-year-old Marinette sat on the lower platform of Paris's famous tower, waiting for her partner to arrive. Strapped to her back was a backpack, heavy and round from having the miracle box stuck inside. It was the only content, minus a letter she had removed from it when she arrived. Her nerves were jittery at how this may go.

She had given this a lot of thought over the last couple of weeks, and it had been the single hardest decision she had ever had to make, and even now she wondered if she was making the right choice. Even Tikki was unsure, but understood why the choice had to be made. It wasn't like Marinette really had a chance. As guardian of the miracle box now, it was her priority above all else.

The pit in her stomach worsened when she saw the black shape moving in the direction her partner finished his patrol from usually. They split the city up, after all. Or they did.

She watched as Chat Noir used his staff to pole vault the last bit from the city streets, landing with the grace of his namesake, and put the staff away and joined her on the lower deck. Marinette found herself unable to meet the gaze of her partner. He failed to notice and plopped himself down beside her. "Good evening, Milady."

She forced herself to look his way and gave him a weak smile. "Hey, Kitty."

He sensed something was off. "Something wrong? Why the big backpack, and what's in the envelope?"

Marinette had to fight back the guilt that ate her up inside. "I came to say goodbye."

It was all her partner needed to set the next scene into action. His eyes went wide. "W-What?"

She wasn't able to fight back the tears that fell from her eyes, and they fell down her mask to her cheeks and jaw, before they dripped down. "I have to leave."

"Leave? Why? Where are you going?"

He demanded answers from her, and she supposed she'd be unable to tell him everything, and not where she'd be going exactly. "After Master Fu gave up his role as guardian, I received more items from someone close to him. Inside was the contact information for another miraculous temple. Master Fu had almost gone there right before he sensed Hawkmoth. Fu stayed, and he ended up giving up guardianship of the box. He intended to receive training. He told me was just a kid when he left the temple and didn't complete his training, so I don't have the training needed to be a proper guardian. They will train me, but I have to leave Paris."

"N-no," Chat Noir said. "That's... such bull! You don't have to leave."

"I do," Ladybug told him. Her heart ached when he shook his head.

"What about Hawkmoth? If you leave, it's just me and he can't get his hands on my Miraculous," he said.

This next part would be the hardest, and in order for it to work, they needed to be on the ground. She lightly pushed herself off the deck, and using her yoyo, she lowered herself to the park below. Chat Noir followed her and landed in front of her, approaching her with much more desperation.

Marinette just nodded her head. "I know that. I emailed the owner of the Ladyblog with a video message. For Hawkmoth directly explaining that I'm leaving Paris. He has no reason to attack Paris if the Miraculous aren't here anymore."

"But I'm still here," Chat Noir shot back at her.

"You will be," Marinette explained to her partner, and then extended her hand, her palm facing up and open. "But the Cat Miraculous won't be."

He was taken aback and stepped backwards like he had been injured. Marinette was aware of his pain because she experienced it as well, but she had to protect all the Miraculous that Hawkmoth didn't possess. If it was possible to protect them and became the guardian she needed to be, she'd be able to face Hawkmoth down the line and defeat him once and for all. She wouldn't risk her partner getting hurt trying to fight Hawkmoth alone. And he was reckless enough to try and do it.

"You're taking it?" he cried.

"Don't make this hard. They are waiting for me outside the city," she explained to him. She lifted the letter in her other hand and offered it to him, bringing her other hand back down to her side. "Please take this."

"What is it?" he asked. He still sounded distrustful, and she didn't blame him. Still, he reached for it and stared at it.

"It has contact information," she said. "They gave me permission to keep in contact. An email I made just for this purpose. I will be back, and should you still desire to be Chat Noir upon my return, and with my training we will take Hawkmoth down permanently."

He glared at her and was about to toss it aside in frustration, but she continued. "It has my identity inside as well."

He froze, and his mouth dropped open a little. "Your identity?"

She bit her lip nervously. "It's my proof to you I trust you and I want no one else as a partner. But in order to do that, I need to protect all the Miraculous. When I became guardian, I gave up a right to my own life."

The hurt she saw in his eyes only broke her heart more, and she knew this would only get harder. Despite his flirting and joking, her partner was a sensitive soul. And this was far too much for the young man. He moved forward, but didn't take the paper. Instead, he took her into his arms and embraced her like his very existence depended on it. Marinette didn't react, and only listened as he pleaded with her.

"Then have my life," he begged. "Take me with you. I need you, and I love you."

"I have to go alone," she explained. "Contact can be made at least once a month when we leave the secret location to go into town. But I can't take you with me."

"Please," he continued.

The guilt worsened to a level far worse than any she had in her entire life and hated herself more than even Hawkmoth right now. The choice was out of her hands, though, as the Miracle box was her life now. She would cease to be anything other than Guardian from this day out. Her hands moved around him, and she embraced him. "I care about you," she tried to comfort him. "And I don't want to, but it's out of my control."

She pushed him away and tried to hand him the letter again. This time he snatched it from her, crumpling it in his hands as he gripped it tightly. "I don't need this. I need you! Please."

Marinette saw there were tears in his eyes and they fell down his face. "Chat," she said.

His green eyes met hers, though he said nothing. She reached for him and cupped his cheek and wiped away the tears. Marinette saw he was in pain, and she still had to leave, but she wanted him to not hurt as much. She had a parting gift, something she hoped he'd fondly remember. She moved closer to him and leaned in. Just as his eyes widened, she closed hers and pressed her lips against his in a sweet kiss. He was only stiff for a moment, and his body relaxed, his mouth moving to taste her. Matching his movements, she did the same, taking the time to return his passionate act. Her hand moved to his shoulder, bracing herself as he fully enveloped her with his kiss.

He took the chance to grip her on either side of her shoulders, her letter still gripped in his left hand. His right hand moved up her neck, and his clawed fingers moved to her cheek where he caressed her. Marinette would be lying if she said there wasn't something burning inside her as the kiss continued, but she didn't lose herself at the moment. Not completely.

Her left hand moved up his right arm, and she traced her own fingers over him like he had just done, and she held her hand on his. Her hand touched the miraculous ring under her palm, and she knew she'd have to burst this bubble.

She pulled from the kiss, though he moved with her at first, but then he opened his eyes when their lips parted. She still felt the tingle on her lips from his kiss, and tears still fell from her eyes. "I'm sorry."

With a movement far too quick for him, she took hold of the ring and slipped it off. As she did, she turned her back to him, shielding herself from a revelation. She gripped the ring tightly and spoke the charm she found in Master Fu's notes. "Duan kai lianjie, Plagg."

Marinette heard the cries of the Kwami she had met once before and saw him forced back into the ring. She had used a charm only guardians could use when gripping a Miraculous connected to a user other than themselves.

The guardian heard Chat Noir's voice. "What did you do?" His voice held anger, and she didn't blame him. Still, she didn't turn around.

"I took back Plagg. If you want him back when I return, use that letter. My identity is in there, but please don't release it to the public. It would put my parents at risk, and you like them and they are fond of you. They are good people," she said. "And Chat... I'll miss you."

It was the last words she spoke before she took off. While transformed, her ex-partner had no chance of keeping up with her, and even though she heard him yelling after her, and he was chasing after, she didn't stop. The tears still flowed down her cheeks and she willed herself to become numb, so she didn't have to feel this terrible pain inside. She gripped the ring in her hand tighter. This would be all she'd have to remember him by. And like it, she'd carry her guilt around for years to come.

A/N: So this is the prologue. I'm sure Marinette wouldn't actually ever leave, but my Scenario is based around Marinette making that choice. It's a dark story with adult themes beginning fairly early on in the story. I hope this story entices your taste buds for now. See you next time!