(AU) Gotham City, 1981. A lonely man by the name of Arthur Fleck sees his life changed by his lovely and young neighbour, Harleen Quinzel. His meeting with this recently graduated psychologist will unleash new, intense feelings in him he cannot bring to properly understand while struggling with a history of abuse that will eventually lead him to insanity. Is Harleen willing to follow her lover in his dark path?

Warning: 18+ ONLY. Older man/younger woman, stalking, implicit daddy kink, toxic/unhealthy relationship, age gap, violent/disturbing/obssesive behaviour, murder, loss of sanity, explicit sexual content.

A/N: This is the first time I write and publish a fic in almost two years. I had the idea after watching a few fan videos (AU or during the film) where Arthur and Harleen fall for each other after watching Joker (2019). I really had fun writing this, since Arthur is a completely new character, not based in comics. I really wanted to explore what he would do if he'd actually had someone in his life to care for him, considering things he wrote in his journal (particularly, 'who's my one and only person...?') about being alone, misunderstood and yearning for love while fighting against his own tormented mind.

I hope you like it!

He had seen her several times, but he never had the courage to talk to her. He usually avoided her when she was too close to him.

Arthur knew himself too well to know what would happen: his hated laughing fits. Therefore, he preferred to love her from distance, without her noting his existence. It was better this way.

The first time Arthur saw this young woman was in the hallway. She was going down the stairs to the seventh floor of the building. He cherished every move she did. This stranger danced while listening to music, thinking no one would notice her. She shook her figure as she mouthed passionately the lyrics of whatever song was listening. Arthur hid near the wall that divided the halls, and thus, the apartments.

He glared at her like a predator. His mouth watery caused by the hunger she woke within him. Arthur swore he could feel her in his arms, dancing vehemently to a song. He wondered during long periods of time how it would feel to touch her skin.

His lust was a loud, thundering storm that kept troubling his already cursed mind. But in the outside, the silence suggested indifference.

It kept like this for months. Arthur had also yearned for innocent things, such as a smile or even a kind word from her. He constantly fantasized about her and the guilt and regret fought after the lustful desires roamed through his fractured psyche. This was too much for him to bear. He wrote about the woman in his journal, dedicating pages of misspelled but honest thoughts. Arthur found a new way to cope with insomnia.

It was a rainy day when his feelings took another radical turn. Arthur returned to his flat after another shitty day of work. He headed towards the elevator, pressing the button to open it. He waited patiently. The bell rang and the sliding door opened.

"Fuck!", he hissed lowly when he saw her. She was carrying a bag and had her hair done in buns. Arthur thought she couldn't be more beautiful.

"Hi" she chirped, grinning at him.

"Hi" was all Arthur could reply after his failed attempt to keep his gaze in the ground. Was she actually talking to him? The beloved stranger noticed a trace of blood in his lips and sweetly asked:

"Are you alright?"

He remained silent for a few seconds, studying her expression. It was so kind and sincere.

"Yes"

"Are you sure you're okay?" Her question echoed through his mind. Even her voice turned out to be as smooth as her appearance. Arthur inhaled deeply.

"I am, miss. Thanks for asking" he replied puzzled, trying to figure out why would she even care.

The door opened and she politely waved goodbye to him and wishing him well. Arthur didn't give a verbal answer but he certainly waved back to her.

Arthur smirked. And his gesture did not disappear until he arrived home.

He built a routine in his free time. If he couldn't be with her, he was satisfied enough to watch her. At night, he usually followed her to the now empty playground. The woman was swinging in a rope made out of clothes stretched and extended in what seemed a big, dome-shaped cage like. The blonde had the habit to exercise there, not bothered by some bystanders (mostly men) who whistled at her.

Despite the jealousy that grew within him, Arthur understood it wasn't strange. He surely wasn't the only one after her affections.

He took a liking to this new scene: watching her move as if she was practising a gymnastic routine was fantastic. Her movements were so delicate, yet sensual. She seemed to go along with the air, soaring with it.

But she didn't notice, obviously. The girl would probably had gone running and screaming for help if she had discovered him.

Arthur was wrong. He was so wrong.

One day, he sneaked around wearing his yellow hoodie to preserve his identity. He was outside the building, hiding in the shadows. There she was again: beautiful and unreachable. Her long, platinum blonde hair fell like a waterfall. Arthur was amazed. She moved her arms in a graceful way once again, to flow through it in a twirl that swinged her back and forth.

The girl seemed to smile before the risky move, congratulating herself in silence on this apparent progress. Arthur laughed out loud, amazed. But he soon clasped a hand in his mouth. She turned around immediately to his direction. Arthur felt the panic and tried to run.

She called him. Not berating him but genuinely interested. There was no violence in her voice. Arthur argued with himself over and over about if this was a good idea from the beginning. The man was walking around like a disoriented dog while grasping his curly locks, out of fear and guilt. He stood still for a while, without saying a word.

He then realized the woman kept calling him.

Arthur tightened his eyelids, fighting the urge to run away. He kept still during long seconds until he finally decided to face her. It was now or never. Little did he know that she was just a few feet away from him.

Once Arthur turned around, he almost tripped taking a step away from her. He stared at the young woman: she showed no signs of fear or disgust. In fact, she seemed curious about him. She clawed at the fence that separated the playground from the building and dead end alleys. He imitated the action, staring directly at her eyes, blue like summer sky. She smiled at him, her perfect teeth shining like pearls. And it was in this moment when Arthur could pay more attention to her attributes. The girl in question was the owner of an astounding beauty: expressive blue eyes, pink full lips which formed a sweet smile. And that was only her face. Arthur was infatuated. Her face lit up once her lips curved into such expression. Was she hypnotizing him?

He wouldn't mind, of course.

Arthur stared at her mouth, and wonders how it would feel against his own cracked, dry lips.

But her body was another wonder. She wore a white, long, sleeveless shirt adjusted to her body shape, leaving nothing to imagination. God, if he only could trace his fingers down her hips he'd die happily.

He continued his private appreciation watching the grey shorts that left her most of her thighs uncovered. He then darted his eyes up to her hair. Her long, slightly wavy strands of hair were dyed in two different colours: the right side was strawberry pink from the half down. Same with the left side, except the colour was a electric blue. It added a dreamy touch to her.

Arthur pictured himself playing with her hair, doing little curls with it. It looked so silky.

"You've been enjoying my show, have you?"

Arthur looked up to her again.

"Yeah" he muttered, ashamed.

"Why the long face, babe? It's not like I'm upset", the woman said.

Arthur stared at her again, but out of confusion.

"At all" she quickly replied, "I like when people see me, actually".

Arthur felt a cold shudder in his back. It was in this moment he sensed something in his chest. He perceived it as the natural reaction to the first conversation he held with someone else without the other significant being weirded out of him. This common trait was enough to give him hope of a new, happy chapter on his mirthless life.

"Yeah... You know, I like when people see me too".

The woman nodded and leaned her face into the fence. Arthur took a deep breath and it didn't take too long to emulate the pose. She was bold enough to let him come closer to her as if she wanted him to kiss her.

"What's your name?" He hummed against her face.

"Harleen Quinzel", she answered "and you are...?"

"Arthur" he rushed to give his reply, "my name is Arthur Fleck-" a treacherous chuckle escaped his throat.

'Oh, no. Not now, not now please', Arthur silently begged as his loving expression fade away so shame would take its place.

His brain of course showed no mercy.

The laughing fit lasted almost ten minutes. It was the first time in years that he truly believed he was going to die of suffocation. He struggled with choking more than two times every minute. Arthur wasn't completely drawn into his fit. He looked for a fraction of seconds at the girl. Harleen shocked at first. After a few moments, she joined him believing innocently he was laughing out of amusement.

"You know, you can tell me the joke so we can laugh together".

Arthur wasn't able to silence his noisy curse. He only covered his mouth, shaking his head trying to make her see the desperation in his eyes. Harleen's facial expressions morphed from fun to actual worry when Arthur's hand reached his throat in an useless attempt to breathe, still clawing at the fence with the one that left free. Her eyes widened in horror. Arthur felt too powerless to even show her the card explaining his fucking condition. It was alright if she wanted to run away. He already accepted his shameful defeat.

However, to his surprise, she nimbly climbed up the fence to help him. The stalker was too weak to keep standing but when he was crumbling into the ground, Harleen helped him to stand up.

She spoke to him, reassuringly. And she spoke so many things he couldn't process while taking him to a bench to contain him. So far she was a few seconds ago and now she stood with him throughout the painful laughter.

"I'm sorry-" Arthur tried to hide his face in his arm but Harleen seemed to understand... Or at least took pity on him.

The laughing fit finally ended and Arthur got a card from his pocket. He remained silent, disgusted with himself. The blonde took it and read it carefully. Her serene gaze towards the object comforted Arthur slowly. Once she finished reading it, she returned it to his owner. Harleen seemed truly surprised... Or maybe scared. He didn't know and felt too embarrassed to even talk to her. One thing was for sure:

Arthur Fleck never felt uglier in his life.