Author's note: I know I shouldn't, but if the plot bunny insist, then I must write. This story was inspired from one of the episodes in season 2 called Syren and a mermaid tale became my muse. However, there's not huge spoilers, just certain elements from season 2, but the plot is all mine.

Enjoy:}

Disclaimer: Don't own Miraculous Ladybug

Prologue: True Love's Promise

Bright white-hot stars twinkled above the entire darkened sky and it reflected down the River of Seine like a transparent mirror. A bleak, grey stone bridge hovered over the river like a shadow. The Dupain-Cheng family stood upon the Pont des Arts bridge, where they eagerly got their ice cream from Andre's cart and enjoyed eating it outside the cool spring air. Tom and Sabine looked at each other lovingly as they shared their vanilla ice cream together. According to popular legend, whoever shares Andre's ice cream would fall in love forever. The Dupain-Cheng couple is a proven fact to this legend. In fact, Tom had even put an engagement ring in their shared ice cream to propose to Sabine and they're still happily married to this very day. Their eleven-year-old daughter, Marinette Dupain-Cheng, stared wistfully at her parent's radiant affection for one another. Most children might be grossed out by their lovey-dovey parents, but not for Marinette because she found her own parents so adorable.

She wanted what her parents had, which revolved around a fairy tale fable called true love. Her eyes moved away from her parents little bubble, towards the river black as night and pondered how deep the river could be. Something caught her eye, she hitched her breath and leaned a lot closer. Huge bubbles became blubbered in the water, almost as if someone had used their breath to blow them out, and this intrigued her even further. However, due to her familiar clumsiness, she found herself dangling off the bridge. A loud scream escaped her throat as she splashed into the water. As soon as her entire being became consumed in the water, she quickly tried to rush up the surface, but something physically stopped her from doing so. Marinette felt her throat taunt itself, from the lack of air she couldn't breath in, and black spots began to blur her vision.

"Human flesh, how delicious, you would be a delight to eat." Marinette shivered when something slimy caressed her skin. She then bit her cheek hard when something pricked her arm like a stinging needle. Fiery blood combined itself with the inky blackness of the water.

"Your blood smells so good, I did right to come to the human's realm, and wait patiently for someone like you to be my prey." Marinette could decipher the voice as male and he frightened her to tears. She could see his face, despite her vision being disoriented, and his mouth became wide open like a black hole. Many razor sharp teeth nestled itself in his black gums, waiting to devour this child's creamy skin.

Marinette instantly shut her eyes, reminiscing her parent's love for her and the love she had for designing clothes. However, the raw pain never came upon her skin, she instead heard the most melodic voice that ever rang in her ears. It blocked out the screeching horror from the akuma when Prince Adrien used his syren ability to kill it off. A royal blood syren's voice could be the most deadliest, especially towards an akuma because it's heartbreaking for them. An akuma was once an enchanting syren, but the evil Sea Witch named Le Paon turned them into victimized akumas.

The young prince didn't even glance at the ashes as he swam towards the unmoving human. Ever since his mother Emilie Agreste died, he has taken refuge in the only human portal, which severely represented his home if it was above land and people walked on their feet. What his mother and him both had in common... their fascination for humans. His mother always referred to him as her darling catfish because he always had heavy curiosity. Every day, he would try as he can to sneak off from his boring heir lessons, and just ethustically observe the humans. Adrien thanked the stars that he decided to come here way past his bedtime. If he hadn't, he would have never gotten the chance by saving this beautiful creature from the dreadful akuma. Adrien wasn't a volatile syren, but something inside him snapped when he saw the akuma having his bloody scales all over her. As he held his princess in his arms, he quickly put an air bubble over her head, and prayed to the gods that she would wake up. When she still hadn't awaken, he let out a huge wail that only a grown syren could produce through their vocals, but he somehow managed like it's a part of him.

The heart-wrenching voice compelled her to open her eyes, no, it had a sense of desperate pleading in its tone. Marinette bleary opened her eyes and gasped at the most greenest eyes she had ever seen. They reminded her of a rich seaweed, which would tie her to the depths of ocean. She then let out another gasp, not another gasp for her to greedy to suck in air by this strange bubble, but by the body that wrapped around her protectively. He had dark black skin, green scales on his shoulders and elbows, and a pale face except for the black skin circulating around his jade eyes. He had wavy blonde hair, with black circular horns attached on top of his head, and his feet connected together to make a two-pointed green fin.

While Marinette openley gaped at Adrien's apprreance, he too was doing the same, but he was being a lot more subtle. Her lovely black hair was tied in twin-tails, even though he desperately wanted to untie them and let them loose like soothing waves. Her bluest eyes captivated him like no other, almost like he was under a syren's spell. His father said when he would become of age, a mating performance shall be held until he has found his Heart's Mate. However, it seemed that wouldn't be necessary. Already, he could feel their consuming bond pulsing through him, almost like an alluring carrese.

"Who are you and what are you?" Marinette whispered as she finally snapped out of her stupor.

Adrien immediately put his head up, the moment he heard her sweet voice, and he almost wanted to hear her sing. He thankfully understood her, he was about to tell her his name, but then he stopped himself. For some reason, he didn't want to give her his prince name that always distanced himself from anybody. No, he wanted to give her a nickname that showed his true-self, instead of the fake mask he always performed.

"Chat Noir," He finally answered, combining his mother's nickname towards this new nickname, just for his Heart's Mate to say only.

She stared at him for a long moment, as if she knew he lied to her, but something in his expression must have eased her doubts.

"My name is Marinette and I'm assuming you saved me. Thank you by the way, I thought I was going to be…" Her voice wavered when the whole situation finally dawned upon her. She could have died, she would have died if Chat didn't save her, unless he's toying with her. Something made her physically coil at the thought, almost like her entire soul is yelling at her, for even coming to a possibility that Chat could ever harm her. A sense of purring vibrated her entire body, which melted any of her thoughts or suspicions, and she found herself immersed in Chat's comforting purring. Marinette, Marinette, Marinette, the name chanted itself like his own Syren song. He wanted to know more than her name, he wanted to know the aspects that made up Marinette.

"Chat, I need to see my parents, they're worried sick about me," Marinette said with a hint of reluctance in her tone. All together, Chat's constant purring stopped and he looked at her like she broke his very heart. Sure, Marinette's first priority should be to ease her parents devastation, it almost seemed laughable that there would be any other priority. However, being with Chat Noir has clouded as this her first priority, since something in her entire being would grieve if she departed from Chat.

"I don't want to leave you Chat, I feel like it would physically hurt if I do, but I can't let my parents worry about me any longer," She admitted with a choking sob.

Chat took a deep breath to gather himself before he slowly took off his ring. He stared hungrily at the drips of blood leaking out of the scratch from her arm, but he refrained himself as his ring devoured the blood to heal her. She stared at him in awe while he gingerly put his ring on her right finger. The ring would dim their bond for one another, until he has come of age to bring her back to him. They could only connect inside their dreams or in a unconsciousness state. He would remember her, but sadly her memories of this night would be locked, which broke a piece inside of him that might never be repaired. Nonetheless, it would be the best for her safety once he grew stronger towards his inheritance, and no one would hurt her for being a human.

He slowly put his hands on her cheeks, giving her a watery smile. "My kiss would turn you into what I am, a catastic syren. So this would have to do for now, until we see each other again my enchanting princess." Before she could blink, he put his lips upon her cheek and an uncontrollable heat consumed her body. She looked at him with tears in her eyes, but when she blinked again, the beautiful syren was no longer in her vision and no longer in her memories.

Thoughts and thanks for reading:}