A/N: This is a new version of Harley's backstory that takes inspiration from a variety of DC canons.

For reference, Harley's outfit in this fic is the roller girl outfit she wears at the beginning of the "Harley's Holiday" episode of Batman: The Animated Series.

A big thank you to my beta writer for this fic, the lovely notearchiver! I really appreciate your help!

For three months, Bruce placed any location of significance to Harleen Quinzel under constant surveillance, bugging the homes and offices of anyone else who might know where to find her. Hours were occupied diligently watching the cameras at her apartment, at her workplace of Arkham Asylum, even at Ace Chemical Plant, and then listening to the conversations he'd recorded. But in spite of all his efforts to catch a mere trace of her, there had not been a single sign she even was alive, not until now.

Deliberately making his presence known, Bruce approached her openly, the snow crunching under his feet. The night was crisp and clear, the stars gleaming in the sky, but the snowfall from earlier in the day still blanketed the cemetery. The reflection of the moonlight on the winter landscape brought the surroundings to glow with an icy sheen.

"Hey, Bats," Quinzel said cheerfully. In addition to her physical appearance and presentation being drastically altered, her voice was markedly different as well. Gone was her cool professional tone; in its place was an exaggerated accent that sounded like a blend of colloquial New York and New Jersey dialects.

"Hello, Dr. Quinzel," he said. "I haven't seen you in Gotham for several months."

"Yeah, I've been laying low," she replied. Though her back was to him, she didn't cast him so much as a glance. A crinkle of cellophane from her arms — mostly likely she had brought along a bouquet of flowers. "I was with Ivy for a while. She sends her regards."

"Poison Ivy?" Bruce barked. When Quinzel first began work at Arkham Asylum, Poison Ivy had kidnapped her, using her as a hostage to cover her escape. A massive manhunt had ensued, and it was nearly two weeks later when Quinzel surfaced, insisting she had never once been harmed by Ivy and that "Pammy is more misunderstood than she is malicious." From the manner in which Quinzel had spoken of her, Bruce had since suspected that in addition to suffering from Stockholm Syndrome, she held romantic affections for Ivy. "Were you her hostage?"

Quinzel shook her head, still facing the other way. "Nah. She let me crash at her place for a while. But we went our separate ways. With our opposite career paths, the two of us aren't quite ready to settle down together just yet."

Definitely romantic, then. "Yes, I've noticed your change of vocation," Bruce commented. "Superman told me about how you helped him force the Female Furies back to Apokolips. Flash and Wonder Woman reported that you stopped by to give them support during desperate moments." The acknowledgement of her heroics wasn't merely for small talk; the goal was to have her explain her motives.

He heard the smile in her voice when she replied. "Were you checking up on me, Bats?"

"Why did you return to Gotham?" he asked bluntly.

Finally, Quinzel turned look at him head on. "Well, I know the superhero genre, and I'm trying to be a superhero. I guess you could say that Gotham is my origin city."

When Quinzel had been the psychologist of Arkham Asylum, she'd dressed like a school teacher, wearing skirt and sweater sets almost exclusively, her hair pulled back in a traditional bun. But now she was clad in some outdated roller girl attire, complete with skates on her feet and pigtails in her hair, seemingly unaware of the cold despite the clothing's insufficient coverage. Her one time fair complexion was now inhumanly pale, and her golden hair was now platinum blonde. Both were bleached to their current shade by the same the chemicals that had transformed the Joker into the monster he had been.

The same chemicals the Joker had thrown her into after he captured her, in a twisted attempt to force her to repeat his tragedy.

"You want to understand me, isn't that right?" He had asked mockingly, holding Quinzel tightly as she tried to fight back, her attempts relentless but futile. "Well, Doctor, here's your chance to relive the experience!"

Only seconds away from reaching them, Bruce had watched in horror as Quinzel plummeted over the edge — but her struggles hadn't been for nothing, as she managed to drag the Joker with her. Together, they plunged toward the tanks.

Using his grappling hook, Bruce had wasted no time in going to extract her from the chemical bath, but there was no need. In the mere seconds needed for him to move from the platform to the ground, Quinzel was already crawling out of the vat to make the same discovery as him: the Joker had landed at precisely the wrong angle, his neck making contact with the rim of the vat at full force and breaking, killing him instantly.

"You're thinking about it, aren't you?" Quinzel asked quietly, all traces of joviality absent from her voice. Her blue eyes, one of the few aspects of her appearance to remain unchanged, burned brightly in her face. "Just because I'm here."

"Dr. Quinzel," Bruce began, but she cut him off.

"It's Harley Quinn these days, Bats. You can call me Harley. And hold that thought, whatever it is." She knelt down in front of the headstone, which that of Guy Kopski's, the man who had been her fiancé before his abrupt death. Setting the bouquet — roses, Bruce noted — on the ground, she gently ran her hand over the engraved name.

"I'm so sorry," Bruce heard her whisper.

Her words piqued his interest. Kopski had committed suicide, killing himself immediately after murdering a homeless man. Both actions had shocked everyone who had known him, considering the violence to be grossly out of character. During Bruce's initial profile of her following her appointment at Gotham, her involvement with Kopski had popped out as one of the various red flags in her background, another being her improbably young age. Now, Bruce wondered if Harley knew more than anyone else about Kopski's death and victim.

Harley straightened and glided over to the main path, having surprisingly little trouble with movement despite the snow. "Walk with me." She outstretched a hand to him, but he ignored it, instead keeping his arms ready at his utility belt as he strode alongside her.

Together, they exited the cemetery and proceeded toward the downtown. They were completely alone on the street; at almost midnight on Christmas Eve in the suburbs on the quiet of Gotham, no one else would be out or awake to see them. For several minutes neither of them spoke, the only sounds the crackle of rock salt beneath their feet and the clatter of Harley's skates.

Harley was the one to break the silence between them.

"That's one of the reasons I was reluctant to come back," she said, her tone still subdued. "I didn't want to be like some sort of ghoul haunting you, reminding you of the Joker. I remember how you tried to save me, and how you visited me in the hospital. Hanging around Gotham would've been an awful way to repay you."

Beneath his mask, Bruce frowned. He'd checked on Harley as Batman the first chance he'd had, but at the time, he'd thought her to be completely unconscious. And by the time he'd gone as Bruce Wayne to officially visit the next morning, flowers in hand, she'd already vanished.

"Why did you leave the hospital?" He asked. "You couldn't have completely recovered in the eight hours you were there."

For a moment, Harley hesitated, then spoke easily, her tone buoyant once more. "Back when Pammy first kidnapped me, she gave me an injection of some special science stuff. Y'know to give me immunity from her poisons. But it did some other things, too — I shot once and was better in just half a minute!"

"So whatever Ivy did, she gave you enhanced healing," Bruce observed. "Is that why you were able to leave the hospital as soon as you did?"

"Well . . . not exactly. " Harley reached up to grab a banner post jutting out of the streetlight they were passing under, lifting herself upward and flipping over to dangle upside down. "You see, Bats, ever since Pammy and me became friends —"

"Ever since she kidnapped you," Bruce interjected sternly.

"She's been looking out for me. She'd get back at anybody who messed around with me at Arkham. And when she saw on the news that the Joker kidnapped me, she rushed to the hospital and got me out." Harley sighed happily. "Such a great gal, isn't she?"

"She was probably more concerned about the immunity formula being discovered than she was about you," Bruce bluntly informed her.

"Oh, yeah?" Harley challenged, dismounting the post and skating up to poke a finger at his chest. "Pammy knew the immunity would react with the chemicals at the plant, and she swept in to rescue me from any horrible experiments awful, immoral scientists might try once they realized how unique," she skated back to grab the streetlight and whip herself around it, "I was. And then Pammy and I got to be the ones to play doctor ." She shimmied her hips provocatively to emphasize the last two words.

"If you're serious about being a hero, you can't be having romantic rendezvous with supervillains," Bruce warned.

Harley scoffed. "Bats who live in cats' houses shouldn't throw stones."

Ignoring her remark, Bruce continued his hunt for information. "What did Ivy's tests find?"

"Besides enhanced healing?" Grinning, Harley ticked the items off on her fingers. "Strength, speed, durability, and agility — all increased! I still can't fly, though, so that's why I have these rocket skates." She outstretched a leg to indicate her footwear. "Whaddya think? Will I be able to make it as a hero?"

"Hm." Though Bruce would never give any outward sign that he was impressed, only a fool would consider Harley's newfound abilities to be insubstantial. She might have some degree of imperviousness to environmental conditions as well, he theorized, which would explain why she didn't seem bothered by the cold despite her inadequate preparation for low temperatures.

His response earned a snort from Harley. "Gee, thanks. Whatta compliment."

"None of your abilities mean a thing if you don't have proper training," Bruce said flatly.

Harley shrugged. "Well, I've kept in shape with gymnastics since I left college, so I've got that, at least. But yeah." She twirled around him, pivoting from heel to toe as she skated. "I'm a total a rookie. Think I could go to Wonder Woman and convince her to let me be an Amazon?" She paused at a shop window to admire its elaborate decorations. "I would love for her to tie me up with her lasso . . ."

Immediately, an idea dominated Bruce's mind: to promise Harley he would train her. But the prospect brought him to battle with himself.

Offering to train Harley was reckless and impulsive; Harley seemed reckless and impulsive, given that she'd absconded from the hospital to keep company with one of his most lethal rogues. And what of her potential involvement in Kopski's death?

Then again, in all likelihood, Harley hadn't been coherent enough to leave on her own; that part was probably Ivy's decision. And if she ran, it was undoubtedly a reaction to the trauma of her kidnapping and trauma at the hands of the Joker. As for Kopski, he would continue to examine the event's circumstances to see what conclusions he could form regarding Harley.

Every facet of his doubts was all the more reason to keep an eye her, Bruce reasoned, watching Harley gaze through the glass, her back leg extended in a partial pirouette. By forging a connection with Harley, he could ensure that she was stable and reliable — perhaps even convince her to attend counseling. He could have her blood tested to discover the injection's contents. Besides, better to have her as an ally with him than risk having her alongside Poison Ivy against him.

"I'll train you," he said, his voice betraying no indication of his doubts.

"What?" Harley turned from the window display to look at him questioningly. "You say something?"

"I'll instruct you on the combat and strategy skills you'll need out on the streets," Bruce said. "It won't be easy, but it's up to you if it's worth the effort." He eyed her roller girl outfit disapprovingly. "You'll definitely need to find an ensemble with better armour if you're going to be routinely engaging in combat."

"Oh, Bats!" Harley bounced up and down on her skates. "Do you really mean it? Are you really going to take me on as your apprentice?"

"As long as you're willing to learn, I'm willing to teach you," Bruce said, already questioning at the wisdom of his words even as he spoke them.

With an ecstatic squeal, Harley launched herself at him, enveloping his shoulders in a hug that he did not return.

"This is phenomenal! This is terrific! I work best in teams, that's one of the reasons me and Pammy got on so good, and I . . ."

As Harley chattered on, it occurred to Bruce that at this point, he could no longer ignore the other reason he wanted Harley to work alongside him: at least some of the blame for her transformation fell on his shoulders. Had he been able to rescue her from the Joker, she would still be a psychologist at Arkham, working to help people as a civilian. But his failure cost her normalcy, her job, her identity — now, every time she glanced at a reflection of herself, she was forcibly reminded of the miserable excuse for a human who made her that way.

The Joker.

Countless times Bruce had debated with himself, going back and forth on the morality of killing the Joker versus letting him to live, which would allow him to kill countless others. On each occasion, Bruce had concluded that he could not cross that line; he couldn't give in to impulse and become a murderer just because it would make his mission easier.

But his morals had a price: the ever rising body count, countless injuries, shattered lives, all wrought by the Joker. Dr. Harleen Quinzel was one of infinity.

Bruce could have saved her. Maybe not that night, but maybe a year before, or fourteen months before. If he had killed the Joker, Harley would still have her life. His goal was to end crime in Gotham, to prevent anyone from going through the pain and loss he had as a child, but here Harley stood as a testament to his shortcomings. Really, what choice did he have but to help her build a life as a hero?

The tolling of a nearby church bell dragged him from his musings; the clock had just struck midnight.

"Well, it's officially Christmas!" Harley darted ahead of him to the sidewalk corner to gaze up at the night sky, and then circled around to him again, expression abashed. "I gotta confess, Bats. You gave the best Christmas present I could ever dream of, but I didn't get anything for you."

"It's not a problem," Bruce said dismissively, but Harley paid him little attention, instead glancing up at the overhanging shop roof.

"Hey, look at that!" She exclaimed, pointing upward. Looping around the roof's edge was a fir garland of pinecones and mistletoe.

Bruce went to quirk an eyebrow at her; after all, it was just a standard seasonal decoration that very common to stores and other businesses. But in the next instant, before he could make any remark along those lines, Harley pulled him into a fierce, fiery kiss.

He predicted the movement, knew what contact was coming, and was ready to push her away — his hand was already on his belt in anticipation of an attack. But her lips were warm and soft, and he could feel the contours of her body pressing against his. Yes, it was a show of weakness, a display of unprofessionalism, and an action he should have never allowed, let alone reciprocated. But for just a moment, Bruce desperately wanted to pretend that he hadn't failed her, that the Joker hadn't succeeded. And so for just a few seconds he kissed her in return, giving in to the warmth and passion of her embrace. The decision awoke roaring hunger within him he wasn't even aware existed, urging him to deepen the kiss, to draw Harley as close as possible and hold her tightly to feel every one of her movements.

The impulse caught Bruce by surprise, an occurrence so rare that it left him unnerved, leading him to end the kiss altogether. But a flame had ignited within him, a flickering warmth he could feel spreading throughout his body, one that he knew he would have to resolve if he was going to be regularly working with Harley.

She stepped back and grinned at him, apparently not offended by his reluctance. "And that's my Christmas present to you, Bats." She leaned forward again, giving him a quick peck on the cheek. "As much as I hate to pull a Cinderella on you, I've really got to run. I've made Christmas plans with some friends over in Metropolis."

Bruce gave a quick nod, ignoring that his lips were still tingling from the intensity of their kiss. "I'll come find you in a few days to begin your training."

"Looking forward to it. And I hope it's a challenge!" The bottoms of Harley's skates ignited, morphing into miniature jetpacks that lifted her into the air. "Merry Christmas!" She blew a kiss to him before soaring off into the night sky and vanishing among the stars.

Returning to the rooftops, Bruce mentally credited Harley's enthusiasm. The Joker may have destroyed her professional life, but he hadn't been able to dampen her spirit.

The thought brought a realization to dawn on Bruce in that moment: the Joker hadn't won. All along, Bruce had believed that because he wasn't able to rescue Harley from the chemicals, the Joker had prevailed. But he was wrong.

Yes, Harley's life was drastically altered. Arkham Asylum had preemptively removed her from her post, and the harsh reality was that she was unlikely to ever achieve much in the professional world, given that she bore an unmistakable resemblance to the Joker. And none of that even began to touch on the lasting impact of the mind games and mental cages the Joker had doubtlessly used to ensnare her during their sessions.

In his determination to have the last laugh of tormenting and mocking her before killing her, the Joker had probably only brought Harley to the chemical plant out of pure sadism. Bruce wholly believed he was attempting to kill Harley when he threw her from the platform.

But in the utmost ironic twist, the last act of Gotham's most monstrous psychopath was to indirectly and unwittingly create a hero. Not only had Harley survived the encounter, the same one that ultimately killed the Joker, she had emerged from it a hero. The Joker had let his tragedy twist him into a ruthless maniac, but Harley had taken a stand, refusing to let misfortune prevent her from helping others.

Finally, a positive outcome resulted from the Joker's actions. Harley's defiance, her refusal to follow the Joker's path, was her ultimate victory over him.

A faint smile stubbornly pushed through Bruce's stoicism. Maybe there were such things as Christmas miracles, after all.