Author's note: This is based on Harley's and Joker's relationship as portrayed in Suicide Squad, which is quite different from the original portrayal in a number of ways. Based on Margot Robbie's Harley Quinn and Jared Leto's Joker. Contains sexual content and graphic depictions of violence.

PART I

Embrace me in your destruction
Only you can show me the darkness

.

You keep my heart under the cover of night
Could be the devil in a clever disguise
Temptation leads us, it's too late for goodbye
Your secret's safe until there's blood on my hands
- State of Seduction, Digital Daggers

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There were three hours every week that Harleen Quinzel dreaded and longed for. Alone in a room with her most notorious patient, only a frail table between them.

Since the first moment she laid eyes on him, she knew she wanted him. And she had never wanted another that much, not in this lifetime or in any other. He intrigued her; she had wanted to know more, dig deeper, and suddenly she had fallen over the edge. She thought she was going to unravel him and gain access to his deepest secrets, but he had flipped the cards on her.

The insane feeling he had set off in her, it ignited a spark and pushed her into endless craving, a bottomless desire that spread like wildfire through her mind and infected every cell with her need for him.

She couldn't get used to his presence; he kept her on the very edge with a single word, a glance. She couldn't find her balance anymore, not that she ever had. None of the other psychiatrists wanted to work with The Joker anymore, so when she was assigned to him, she had no choice but to accept. But soon enough she realized that seeing him had become an addiction, destructive, wild, and so good.

It had turned into a habit. The evening before their weekly sessions, she would make breathing exercises. She told herself that this time, she would be completely in control again. No more fooling around and laughing at his jokes, no more forgetting what she came for and playing along with him; time to get real.

She must get something out of him; she was not a visitor at a museum admiring his work of art; she was the artist and she drew the line, figuratively. Her job was, unofficially, to shape his mind back into its default shape, to force him back to sanity by all means necessary. But lately she found that the more she tried prying, he would only get further away.

She would soak in the bath, wash her hair and drink calming herbal tea while arranging her notes and preparing the exercises. But over and over again, her concentration was cut off by the thoughts of him. She couldn't stay calm; the tense feeling in her stomach quickened her breathing again.

She would have to pull herself together, arms tightly wrapped around her body. Get it together, Harleen. Just another therapy session. It's not like he's going to devour you alive - oh, scratch that.

The night before she could never get any sleep. She tossed and turned in the darkness, tried to suppress the mental imagery that so often overpowered her when she let her guard down. She remembered it vividly, the way he would look at her when she entered the therapy room, as if she was the reason he was still alive.

His bright green hair, his pale skin, the tattoos and scars, his ice blue eyes framed by dark circles. His marked jaw line. His eyes, his mouth, his smile. They all warned her for the impending danger; all the red flags staring right in her face.

Harleen breathed through her teeth, but the thoughts kept coming.

His eyes that shifted color in the light, depending on his mood. When he was angry or tense they were steel grey, like the cold barrel of a gun in her mouth. When he was calm, satisfied, or wondering, they were simply pale blue, open and bright.

His smile, when he wanted to draw her in and pull her closer and make her knees go weak, how he lifted his upper lip and showed off his teeth. When he wanted something, coffee or a stuffed animal or a machine gun, he would pull both his lips back as far as they would go, a wide smile that he tried to make as less threatening as possible, for her. As if he could ever scare her away. She was onto him like another tattoo; getting rid of her would leave a permanent, red mark.

He had seemed to notice it as well. She had been forced to skip one of their sessions the previous week due to stomach flu, and the other doctors had told her that Mr. J had thrown a fit that none of them would ever forget, putting half of the staff in the emergency psychiatric room. They had practically begged her to come back to work as soon as possible, which of course she had. It would be painful to even try to stay away from him now.

And his smile, oh God, when he was… furious. When he heard about some of the guards taking a liking to Harleen, or when he found out about one of her other patients trying, and failing, to seduce her. Like a horrifying mixture of a wolf's hungry smile and a shark's wild gape, it threatened to eat her whole. That smile was always followed by someone's decapitation, but she seemed to be immune to his wrath.

Mr. J had a smile for every occasion, and he reserved his best one only for her.

When he gave her his Harleen-smile, eyes intensely set on her and his red lips stretched as far as they could, only showing a small part of his grill, she felt dizzy. Lately she had been more and more tempted to just lean a bit further, closer to him, and…

Anti-social personality disorder, her rationality desperately chanted as she turned and tossed, dreading tomorrow in the bottom of her stomach while her skin tingled with anticipation. Manipulative, a barefaced liar. Impulsive. Charming. Attractive.

The way he purred when he was pleased, how his eyes seemed to see through her façade, down to her very core. He saw a part of her that no one had ever seen. The way he made her body ache for him, and he was not even in the room.

Addictive.

Harleen took a deep breath, tilting her head back on the pillow.

A sexual narcissist.

She bit her lip hard, letting her fingers trace her skin, going beneath her nightgown.

.

.

In the morning she made black coffee and tried to mentally scold herself into focusing. But as soon as she thought about her upcoming patient therapy session, her heart fluttered and her stomach twisted. She would usually end up leaning against a surface for support, doing cramped breathing exercises.

After a sleepless night and overthinking, she was ready to give up. All her emotions had been tied up to a tight knot once she entered the hospital in the morning. She felt like a tense rubber band; if anyone pulled it too hard it would break.

It had been a little more than two months since she was assigned to him, a month since her emotions had a short circuit. She was used to fear not feeling like fear anymore; it was just one part. Fear had the same color as desire, as craving and longing and uneasiness. Every emotion had a bittersweet tang to it; it was impossible to separate them.

Her colleagues had been avoiding her lately. Harleen kept to herself, trying to keep her frail composure. The hours were passing excruciatingly slow and fast at the same time. She could never focus on anything else, knowing he was in the same building, waiting for her. None of her other patients mattered anymore.

Their session was eventually only twenty minutes away. She stood too long in front of the mirror in the staff restroom, making sure she did not have a strand of hair out of place. She splashed her face with cold water while the excitement-dread slowly grew.

Eventually she talked herself into heading for her patient, holding onto the case files tightly and a cup of coffee to calm her nerves. She greeted the guards outside the therapy room and they stepped aside to let her pass, lowering their automatic rifles.

She took a shaky breath.

He was already there, of course, sitting by the table in his filthy straight-jacket. The look on his face told her he was not about to wait any longer.

Harleen put on her best smile. "Hello, Mr. J. How have you been?"

She sat down across from him, putting her folders on the table and opening them to look for the notes she made last night. She was happy she had become so good at masking her nervousness – when no one looked too closely.

"I've been waiting for you, Dr Quinzel," he purred, watching her intensely.

She swallowed the disappointment. Had they not come any closer than this? "Please, call me Harleen."

"Alright then, Harleen," he said slowly, drawing out the syllables. She already found herself staring at the curve of his lips.

"Are you ready for some questions, Mr. J?"

He tilted his head to the side, stretching his lips. It was his way of telling her that he was going to be good and do what she wanted.

What she really wanted…

Focus. Mentally slapping herself, Harleen forced herself to read the questions she had prepared, coaxing cryptic answers out of him.

What do you think about when you see this picture? Elaborate. Describe yourself with ten words. What is your favorite color? She kept herself busy by taking notes, or pretending to. Sometimes he would not reply at all, just staring impatiently at her, and she would have to bite her tongue until she could focus again.

They went on for a while; she talked, and he sometimes replied. Every session was the same: they would play pretend for a while, just so she would have something to report. He did it for her sake, though she knew he hated the silly pre-school games more than anything else. He was a genius; anything she came up with was an offense to his intellect.

It was all such nonsense; she couldn't remember anything of that later. But as long as she kept her gaze glued to the paper in front of her she could keep her pulse normal.

When he stopped replying completely, she was forced to look up. "Mr. J? Does the word 'fire' mean anything -"

His eyes caught her entire attention. Once she started looking at him, she could never tear her gaze away. His eyes held so much; a promise of danger and darkness, but they were the most intriguing ones she had ever seen. Alluring her, capturing her. Scrutinizing her, as if he was the had been studying her intensely all the time. Harleen felt the sweat break out on her palms and her throat thickened.

She dropped the pen.

The Joker leaned forward, slowly stretching his lips into that wolfish smile she should have been terrified by. He might have a silly, dement smile on his face, but those gray orbs were dead serious.

Harleen's pulse rushed; she couldn't remain unmoving in her seat. Slowly, as if she was about to face the guillotine, she bent down and reached out a trembling hand for her pen. She knew his eyes were on her all the time, and when she straightened up she released a deep breath.

She tried to set her gaze on anything else but him, tried to make sense of the surroundings: grey concrete walls, tiled floor, small barred windows. Her neat folders in front of her, his name written on the file, and he was dominating her field of vision again.

Her heart was beating so hard she was sure he knew. Was it possible to feel like a prey but at the same time in control? The man across from her in the straight-jacket was physically helpless, but his eyes, Oh God his eyes, had already conquered her.

There went all her plans and her confidence from the night before. He had won this game again.

"Are you afraid?" he asked suddenly, that wide grin still playing on his lips. He watched her intensely as she fought to keep her composure. She knew him enough by now to realize he was not taunting her.

He actually wanted to know.

She swallowed hard. Her eyes were helplessly drawn back to him and their gazes locked. He was unwinding all the parts of herself she had tied together so tightly. Of course she was afraid. But that kind of fear was thrilling; left her light-headed and breathless. Fear and desire mixed together became fervor.

She shook her head. "No."

"I like you… Harleen," he breathed. "You're not like the others. They were so boring."

She nodded helplessly, her cheeks glowing from the praise.

It was an addiction to be so close to him, the thrill made her blood boil. The way he tilted his head slowly, gaze focused, breathing deeply.

It was so erotic.

"We've become quite acquainted by now, have we not?" he continued, sounding strangely friendly. His eyes bore a hole into her. "You know I live for these moments with you. Harleen. I think I like you... very much."

She didn't know how to respond, if there was anything she could say at all. So she gave in and let her body lean over the table. He showed no signs of surprise as he too leaned in as far as he could reach. Still, he could only get so far before his restraints held him back. Harleen reveled in the fact that she had the upper hand, for once.

"Mr J," she breathed. "I like you too."

"Good girl," he purred. "I'm not planning on saying goodbye to you anytime soon."

Harleen couldn't breathe, he was too close and the adrenaline pumped through her veins. Her instincts were screaming at her to run, to stay back. She saw his bared, pale neck, heard his strained breathing. The craving to get closer was overwhelming. It hijacked whatever part was left of her rational thinking and overthrew her senses.

The Joker tilted his head to the side and his eyes were inviting her, testing her.

She kissed him.

His cold lips on hers were surprisingly soft, tasting like metal and acid. He moved against her mouth, purring.

The infamous Clown Prince of crime was there in front of her, eyes closed, looking almost blissful. She wanted more, raising her hands to push him closer, but he pulled apart.

She tore her gaze away from him and glanced at the clock on the wall. Their session was over, only two minutes left. For the first time she was only disappointed. Her heart was beating painfully fast and the adrenaline still powered her movements. A bit unsteadily she stood up to collect her folders and forgotten cup of coffee. His eyes followed her.

"Did you like that, Doctor?" He sounded a bit out of breath himself, something wild in his eyes. As if the straight-jacket was the only thing keeping him from ravaging her.

Harleen tried to compose herself, knowing her face must be ablaze. She took a deep breath to steady her voice.

"We're finished for today, Mr. J. I'll see you next week then –"

"Tomorrow," he interrupted her with unusual force. "Come tomorrow."

"Mr. J, I have other patients." I'd be with you every day.

His eyes flashed; his words sounded just a bit more desperate than they should have. "Not much longer, Doc. I don't like sharing." He bared his metallic teeth. It was a warning to her as much as to every other inmate and guard in the place. He had enough connections outside to make anyone at Arkham 'disappear' on a whim and end up in the sewers a few days later.

He put on his best Harleen-smile and tried to smooth over his sudden outburst of emotion, but she had seen it. A part of her cheered – he had finally shown her a real part of himself, raw and unhinged. Just the way she wanted.

He didn't need to give her his special smile. She wouldn't deny him anything.

"… Alright. I'll see if that can be arranged –"

"Oh, it can," he purred, ice blue eyes boring into hers. "It will," he added with more strength. "I am not finished with you. And tomorrow, I have a very special request."

Then he smiled again, the fire dissolving from his eyes. "Take care… Harleen."

As soon she left the room, she felt her legs give out.