Author's Note:

When also a belated one. Sorry for confusing you guys, I'm still getting used to this site! Anyway, this is a Celtic Mythology AU, a Twin AU and it starts one year before the origins episodes (therefore pre-Miraculous, so the miraculous will eventually show up, don't worry!). Adrien and Félix are twins and half Cat Sidhe (faerie cats that can shapeshift into the form of a cat and the form of a human respectively) half human. The existence of faeries is not a known fact though, so they constantly have to hide their cat side and pretend to be fully human, otherwise there will be severe consequences. Marinette is a normal human and basically the same as she is in the show, so nothing to explain there. I won't say more as to not spoil anything. :3

If you came here for werecat beasts then I'm sorry to disappoint you, since you'll only get cat-cats, cat-boys that purr occasionally and enough friendship fluff to kill a man. It's also a friends to lovers slow burn, so prepare for that! ;D

On that note, I hope you'll all have fun reading Spellbound! ;3

~ Lilafly

Definitions:

Tír na nÓg = The faerie world of eternal youth and spring. Also referred to as simply Faerie.

Samhain, Imbolc, Beltane, Lughnasadh = Celtic celebrations throughout the year. Will be mentioned in more detail later in the story.

Cat Sidhe (pronounced [cat shee]) = A large black faerie cat with a white tuff at its front. It's the size of a medium dog.

of the Sidhe (pronounced [of the shee]) = of the mounds. Sídhe are faerie mounds under which faeries live. The word is used both when referring to these mounds but also when referring to the fair folk (another name for faeries).

widdershins = counter-clockwise (it's Scottish, so I don't know if everyone knows it. Just thought I'd add it as well)

He knew he shouldn't be out. The obedient son in him bristled at the sheer thought of so blatantly going against his father's wishes. However, in the end, it had been the cat in him that had won the inner conflict, for it was the cat that yearned for freedom the most. That's why Adrien had shifted and jumped out the window before his brother had been able to get a hold of him. Even though he had been anything but deaf to Félix's demands of 'getting his furry ass back inside right that instant', and the excessive cursing that followed when he hadn't done so, it failed to deter him yet he still felt guilty. He knew that Félix was just worried about him and that with good reason.

It had been exactly half a year since their mother had disappeared without a trace on Midwinter. To go out on a night like this, when the pull of Faerie was at its strongest, was dangerous to those who could feel it. How easy would it be to just give in to the songs of times long passed and follow the voices that called him? How easy would it be to slip into Faerie, only to return eventually and find out that several hundred years had passed and all his loved ones were dead? Very easy. So easy, in fact, that his mother, who he had always considered an expert on all things fey, hadn't been able to resist them after all.

Midsummer and Midwinter were no times for settled fae like them to wander around outside. It was a time to keep St. John's wort and rowan sprigs, collected on Beltane, close and suffer through the unpleasant effects it had on them. Humans liked to use those herbs to keep fairies at bay, but Emilie Agreste had discovered that they were just as effective to keep fairies inside a house and prevent them from leaving. Since at home they were safe. The St. John's wort, worn in their hair, would divert the magic of Faerie and not tempt them to follow it.

Yet, that had been when his mother had still been around and made sure to always have those specific herbs and trinkets at hand when the days, in which Faerie's pull was most persistent, came around. Midsummer, Midwinter, Samhain, Imbolc, Beltane and Lughnasadh; those were all difficult times. Even with the herbs helping them, the pull of Tír na nÓg was strong and hard to resist. Emilie Agreste had been confident of nothing bad happening with the St. John's wort flowers in her hair and the only short trip to a shop. She had been wrong. With her gone, Adrien and Félix had been left to fend for themselves at Imbolc, Beltane and eventually also on Midsummer.

Félix had always been the stronger-willed one of the two of them. He had managed to get them the needed herbs but that hadn't been enough. Not when their father had forbidden them from shifting since their mother's disappearance and kept them strictly away from the outside world as best as he could. Therefore, it had only been a question of time until one of the twins would snap and break the no-shifting rule. That it had been Adrien was not much of a surprise, but that it had been on Midsummer of all nights was an absolute disaster.

The pull was strong and the songs of olden times threw him in a daze. They were comforting like a lullaby and beckoned him closer. Not that there would be a certain place where one could cross into Tír na nÓg, the Faerie realm. It just happened when the anchor to the human realm was broken. Adrien desperately tried to concentrate. To find his anchor and return to the mansion as soon as possible. His hackles rose at the mere idea of going back. It had been far too long since he had wandered over the Parisian rooftops at night like this. The warm breeze that blew through his fur further soothed him, making him want to just follow the beautiful music and the voices he heard, even though he couldn't understand the words of either.

Don't give in! He told himself harshly and made a sharp turn, running counter-clockwise to get rid of the daze. That his cat side argued with his common sense was really not making things easier for him as he was torn about where to go. The figures he saw walking through the streets and sometimes even through the air, did not help him to feel rooted either. They were not real, or at least, they were not real at this moment. A long time ago they had been real and they had walked those very grounds. Long before the name 'Paris' had even been invented and before the city had been built. Back then, it had just been roads and small villages scattered around a land with another name and form. What he saw were just pictures of the past.

Not real. They are not real. Ignore them. Run widdershins. Listen to what is real. Find an anchor!

Nearby in space and slightly sideways in time, something like a human figure, just much taller and much more beautiful, strode by, laughing at a joke Adrien wished he didn't understand. Also, the smell – the smell! – was killing him. A smell like fresh-ploughed earth, just stronger and more alive, a smell of living magic full of eerie delight. A smell that was so distinctively not Paris that it confused his senses and made him lose any sense of direction.

Adrien wanted to panic. Panic would mean stress and stress would mean that he could snap out of the daze for good. It would mean that the soothing songs and the sound of horns from a hunt that had once taken place in a forest that was long gone couldn't get to him anymore, if only for just a short moment. He couldn't though. The pull was strong, way stronger than he had ever witnessed it being.

Don't slip! You can't leave Félix alone! He practically yelled at himself inside his head. However, even the thought of his brother could not root him in the here and now for long. He needed something else. A feeling, a scent, a sound, anything! Just something that wasn't Faerie. As of now, he was feeling, hearing, seeing and sensing things that shouldn't wind their way into this reality. Things that belonged somewhere else and which he wanted to stay ignorant of like the humans were.

Green eyes frantically scanned the surroundings of Paris' roof tops. Where was he? For some reason, he couldn't find himself to care much about his location. He could have been just a street away from the mansion without being able to recognize anything. Did Faerie already have that strong of a grip on him? Had it really come to the point that he couldn't recognize his home anymore? He had spent so much time as a child on those very roof tops that he basically knew Paris better from up on them than from down on the streets.

When he took another step, he slipped. Not into Faerie but quite literally. Too deep in his musings of where and how and when, he had not noticed that the wall he was walking on had come to an end, making him fall. He braced himself for the impact of a fall from several stories, knowing that he would be fine. After all, he was no regular cat: He was a Cat Sidhe. A faerie cat ‒ oh, how much he despised the word! He could take a fall, even though it would still hurt.

It therefore surprised him when the fall ended shortly after it began and he tumbled on the tiles of what seemed to be a balcony. At least the scare the fall had given him was enough to snap him out of the daze at least a little. The heavenly scent of roses did the rest. Like all fairies, he was quite fond of the flowers. Just as rosemary and gorse drew fairies away, roses and bluebells drew them in. However, while roses were nice, would they be strong enough of an anchor? Could they chase away the smell of ancient magic that was drenching the city on this dreaded night? He could already feel the daze returning and the songs getting louder now that the shock was wearing off.

In the end, it was a voice that saved him from following the tempting calls again. A voice that managed to root him quite thoroughly.

"Hey kitty, are you alright?" It was sweet and female, soothing him in a way the songs of Faerie didn't. For this was reality, not something illusory. Adrien would have jumped had he not still been in the slight daze of Faerie's call. When he turned to its speaker, he was met with the most beautiful blue eyes he had ever seen. Could humans even have such beautiful eyes? Apparently, since she was definitely not of the Sidhe.

She held her hand out to him, probably for him to sniff like one would do when meeting a cat. He was so perplexed that his cat instincts took over and he did just that. The scent of vanilla, cinnamon and something sweet and floral greeted him. It was a wonderful scent that was much more tempting than the smell of magic.

That was when he realised that he had found an anchor. Thankful and endlessly relieved he nuzzled her still inviting palm and purred. On other days he would have run. Being close to humans only lead to disaster and he didn't want to bring bad luck on this poor innocent girl but tonight was different. Tonight, he was just a lost cat that couldn't find his way home and he was more than grateful to this human girl for saving him, even if she did not know that.

Why was she outside on her balcony at night in the first place? It probably was close to midnight already and she seemed about his age. Thirteen-year-old girls should be in bed at this hour. He placed his front paws on the side of the lounger she sat on and meowed, curious as to what she was doing.

All curiosity vanished however when her fingers suddenly stroked through his fur and Adrien all but melted into the touch. It had been so long since he had last been petted by someone in this form – the last time had been when his mother had still been around. He only noticed that he had jumped onto her lap when she giggled.

"You're a cuddler then, huh?"

He was, even though he probably would never openly admit it. In that sense he was quite glad that the cat in him had decided to take over and succumb to the sensation of her pets. Otherwise he would have died of shame. She didn't seem to mind but that was probably because she didn't expect him to be able to understand her – she didn't know that he knew of social boundaries and manners after all, that he was someone she could have crossed on the street once or twice. She would no doubt throw him off her balcony if she found out and then he'd be back to running from the songs.

The thought of that made him shudder and think about what his mother must have been through before she disappeared. The confusion and the dwindling will to be was something he didn't want to go through ever again if he could prevent it. Therefore, social norms, morals and fae laws be damned, he would stay with this girl until Midsummer would pass. If she would let him stay that was.

He didn't notice that she continued doing whatever she was doing before he fell on her balcony though that was maybe due to the fact that she continued to pet him with her other hand. His purrs tuned out the scrape of a pencil on paper, though he noticed her occasional yawns. It was peaceful, to say the least. He knew he would only stay as long as Midsummer would last – that he would return home at sunrise in two days and never see her again – but something within him didn't like the thought of leaving her.