A/N: Yay, my first Psych fanfic! But seriously, why isn't there a Mary Lightly character tag? That's messed up.

This was partially inspired by a one-word prompt on the Facebook group Writers Unite!, but only partially. So if the word "regret" seems like kind of a stretch, just keep reading, okay?

Reviews are appreciated! I hope you enjoy it.

Her name was Pauline, although, as she told him, her friends would sometimes call her "Paulie," or even "Paul." "I think we've got ourselves a band," she said. "Know any chicks named Peter?"

As usual, he did not understand the joke. But his humorless stare did not make her shudder; she didn't see the awkward pause as a cue to cough and walk away. Rather, it seemed to make her grin even wider.

They met by the veggie platter at his uncle's birthday party. She was using celery sticks like chopsticks to pick up the broccoli, the kind of quirk Mary's mother had instructed him to look for in a friend. If you understand them, they will understand you. So he introduced himself to this bushy-haired celery girl who as far as he was concerned had no relation to his uncle – Uncle Clive was already his mother's sister's husband, and after being pressured into a sip of his mother's champagne, Mary had no interest in further complications.

Of course, that didn't stop her from telling him. "My daddy works at Clive's firm. He's a real big boss." She tossed her thick ponytail to the side, revealing golden earrings.

It seemed like she was bragging. Mary prayed she wasn't spoiled and self-centered. "Who is your father?" he asked as he scanned the room for a man who resembled her. He came up empty.

"Oh, he's come down with the clap," said Pauline with a flippant laugh. "Last minute doctor's appointment left his invitation in my hands. Don't worry, Mister Gentleman." She placed a hand on his shoulder. Her fingers crept around to scratch at the hairs on the back of his neck. "You won't get in trouble for shmoozing me."

Pauline had an obsession with eye contact. She kept her eyelids low and unsuspecting, but her reflexes were quick. Sensitive. Mary, barely out of school and hopelessly naive, could not comprehend what made her crave this metaphysical connection, but she didn't break eye contact as she prevented him from spilling ranch dressing on his khakis and guided him through the hoards of guests to the couch across the room.

"Lawyers," Pauline sighed, allowing herself to collapse over the only throw pillow. "Absolutely obnoxious and looky-here, we're at a party full of them. A Super Bowl of shysters. Just like Daddy's Super Bowl parties." She snaked her neck upwards, and Mary could feel her breath on the underside of his chin as she spoke. "Oh, you would hate him, Mary dear."

Mary doubted it. He tended not to hate people. He could barely stand that word – hate – and he resented being accused of it. But Pauline was strikingly odd and oddly pretty. So he opted to change the subject.

"What I do for a living?" she replied. "Oh, I work for my father."

"Even though you have a distaste for lawyers. Do you do it for the money?"

Pauline broke into a cackle. "A lawyer? Oh, you goof." She drew her hand down the length of Mary's jacketed arm, which seemed to calm her. "As if I would do the same nasty business as him," she said breathlessly. "No, I'm his writer."

"You mean, his stenographer?"

"No, his writer. You see, Daddy's a brilliant speaker but his grasp on written English is sloppy and unpoetic. He writes things to his clients and I edit them. I add the poetry." She smiled devilishly. "Everything needs poetry. Don't you agree, Mary Mary Quite Contrary?"

"I've never agreed with anything more," he answered. In that moment, he felt like he was in the middle of a poem, an ethereal world with half-fictional inhabitants who were dangerously real until the stanza ended and they disappeared. No woman had ever smiled at him as intensely as Pauline did. No woman had ever smiled at him at all, and that made him suspect this was just hyperbole that God was using to capture this strange but simple moment: The Normal Girl Who Once Flirted With Mary Lightly.

But she is very real. He told himself this as he washed his hands in the bathroom, watching himself in the mirror just to prove it was possible – yes, a person could look him directly in the eye. Down the hall, Clive's family and friends were making a loud fuss over the cake. The Normal Girl would have joined them, but Mary could feel Pauline's biting essence nearby – just outside the door, even.

And there she was. When Mary opened the door, there she was, standing in the hallway, with her hair down and framing her head like an approaching thundercloud. He startled slightly the way she attacked him, pushing him back into the bathroom and kicking the door shut behind her. Her hands turned crimson pulling the collar of his jacket into his neck, and her kneecaps stabbed into his thighs. Once she had him pressed against the tile wall, it took him a moment to realize that she was kissing him.

The poem wasn't over. Mary was swept into a manic downpour of Pauline, Pauline with softly calloused hands and chapped lips that ventured, the celery girl, Pauline. He tried to play along, and he did – badly, very badly he did, but she did not seem fazed by his uncoordinated hands and paralyzed lips. Mary had never so much as kissed before, but Pauline was blind to the concept of "virginity," and was already taking it further, unbuttoning and removing multiple articles of clothing all at once – her shoes, his jacket, his shirt, her scarf. His fingernails caught under her ear as her dress went over her head, chipping a speck of paint off her earring and revealing it as sterling silver, not gold. He hardly noticed and he didn't care, because she was unzipping his pants. Outside context did not concern him anymore. The entire world was silent except for their breathing, especially hers, broad and vocal.

This wasn't love, but it had potential. Wonderful potential.

But their potential was not consummated that night. Mary's own mother walked in them before any undergarments were shed, and although she seemed thrilled that her son had made a connection, all good feelings were trampled by her announcement: "Aunt Denise was kidnapped."

The two almost-lovers scrambled into their clothes. Pauline bravely kept eye contact with Mary the entire time, burning an image of her face into his brain for when they left the bathroom and were forever separated by the whirlwind of panic.

Denise Martin was the third victim of the psychopath soon know by the authorities as "The Yin-Yang Killer." Her young husband Clive received an anonymous, rhyming letter on his birthday with an inordinate number of references to his "cougar" wife, but he thought little of it until she mysteriously disappeared in the middle of his party. It was then that he found a stopwatch hanging on the doorknob of his bedroom and the signature Chinese symbol of balance painted on his living room wall in gold nail polish. He followed the first clue quite easily to the cosmetics store where Denise worked, but ultimately he was not the brilliant opponent that the killer expected.

Denise's corpse was found in the lion's cage at the local zoo, sliced open and gutted so the beasts wouldn't have much to munch on. Clive was shell-shocked and rejected any counseling. A week later he asphyxiated himself with car exhaust.

He was never close to his nephew-by-marriage Mary Lightly. But Mary always remembered the last thing he said to him, just before he left the house to play Yang's game: "I don't know a Pauline. Your aunt must have let her in."

Of course, Mary didn't start chasing Mr. Yang just because he interrupted his one opportunity to lose his virginity. He'd studied criminal psychology in school and had been intrigued by the Yin-Yang Killer since the first murder. And death of his only aunt and uncle didn't console him. Then again, neither did the hormones. But Pauline was altogether a different matter. She was personal; Yang was professional. That his two great obsessions began on the same night was only a coincidence that assured everything that he'd worked towards before that night would be moot.

After two years of constant inquiry and fact-checking, he discovered that nobody who had ever worked with Clive had an adult daughter named Pauline.

He spent five more years looking for her at every law firm in the state. He found one secretary named Pauline, but she was approaching age sixty.

He thought he could find her with an online dating profile, but there was no way to filter out girls not named Pauline. He said that he liked celery and editing legal documents, then left it alone to do its work. It was deactivated four years later due to lack of interest.

By the time 2008 came around, he had resorted to pulling aside any woman on the street with bushy brown hair. Pauline's sharp face and unreal energy were things he would recognize even with mace in his eyes, and he simply could not find her.

Mary reminded himself that in the movies, only true love managed to find itself easily. And this was not true love. It was only the closest he would ever get to true love, and because the supernatural theory behind it was both meaninglessly abstract and pathetically obscure, it would always be harder than catching a serial killer. The truth was, he lacked the creative insight of Shawn Spencer – if only the psychic had come along sooner. Then they certainly could have found her. Perhaps not save her, but definitely find her before it was too late.

Before she turned up in a padded white room, not under the name "Pauline" or "Paulie" or even "Paul," but as "Patient No. 02179 – Mr. Yang."

Yang's eyes seemed to have grown. It may have been the spotted dark spots that had sprouted like fungus underneath them, but they looked wider. Her subtle way she'd followed Mary with them thirteen years before was no longer subtle. He now felt as if he physically couldn't look away.

He exhaled from constricted lungs, letting his face melt into the most natural smile he'd made in years. "Pauline."

"Oh, people make that mistake all the time," Yang replied, her face blank. "I know – I don't look like a Mister, do I?"

Mary frowned, suddenly filled with dread. It wasn't possible – she couldn't have forgotten him. Behind him, the tall white door creaked shut as the orderly left them alone.

"Mary Lightly. Dear sweet Mother Mary, it's been a long time. Did you read my book?" To Mary's relief, Yang allowed herself to break into a wide smile. She pushed herself off her bench and crawled towards him, accidentally smacking her forehead against the glass that separated them. She looked up with woozy insanity.

"I did read it," he answered. "It's a delight."

Yang scowled. "A delight? I expected much much more out of your review. You're the first visitor I've got, and do you know how much time I had to work on my prose, slashing phrases and cutting out the accidental rhymes? It's my most brilliant work – but of course I'm biased." A smile popped out of her, so jarring that Mary was compelled to approach, dragging along the frictionless ground in his dead-white suit. "At least tell me what you thought of your special chapter," Yang chirped.

"You barely mentioned me."

"Oh, didn't I?" Yang said. "He has my scent, this gray mutt of a man named after a woman. Mary Lightly, the – "

" – the woeful guardian, squealer of my secrets," interrupted Mary, reluctantly swallowing down the poetry of her writing. He knelt before the glass. "But what about the first time we met?" He stared into her dull eyes, trying to see that sane energy he'd seen thirteen years before. "Pauline."

"Mister Gentleman, you little goof. Of course I mentioned you, dear Mary Mary Quite Contrary."

Flashes of that night in 1995 circled in front of Mary's spectacles. She did remember. But he had to ask, "Are you sure?" He had read the book cover to cover three times in the week since its release, and each read was an emotional knife through the heart. The most important night of his life, and the woman he shared it with didn't find it worth mention.

"Doesn't this ring a bell? 'In a washroom symbolically decked in sunset pink and rose body oil, I had my first homosexual experience with a dumb blonde and her fat ankles. She was an ugly girl, that Marie, but I loved her anyway.'"

That was him? "I'm not a woman," said Mary, his ears getting red under the white hood.

"I know." Yang swept her index finger against the glass, like she wanted to tap him playfully on the nose. "I changed your name to protect your identity."

"But why, Pauline? Having sex with a serial killer would not have been my most shameful moment. Trust me," said Mary. "That would have been awesome."

"Aw, I know where this is going." Yang smirked and stuck out her chest. "Come on, baby, let's play pretend."

"You were forward and lively and you liked me," Mary continued. "The shameful part was losing you in a crowd."

"And they told me the public only falls in love with Ted Bundy types."

"I haven't fallen in love with you . . . I still could, but the point remains. When we were kissing, you were as lost in the moment as I was. You had every intention of going all the way. It wouldn't have taken long. But you didn't know. That's not the kind of thing you do when you're scheduled to murder someone in half an hour. I know you didn't kill my aunt."

Mary gasped, having delivered the entire speech in one breath. And that was the last sound that either of them heard for a while. For the first time, Yang had nothing irreverent to say. So they stared at each other, perfectly still the both of them, him on his knees as if praying to his cross-legged goddess. He had never seen her so still before – as beautiful as she was, he now saw the moldy pallor of her skin. He had never realized how much older than him she was, but she had at least five long, difficult years on him. Her face was gaunt, and he wanted to pity her. He'd never intended to pity Pauline, so he took the other route: he let himself fall in love with her for real.

And why not? He'd been in limbo for thirteen years, knowing everything but feeling nothing.

He knew nothing about Pauline. It occurred to him that her father was not a lawyer and that Pauline might have been an alias all along, but he was still certain that she was not Mr. Yang. She knew him, though. And Mary knew him. And that meant that Mary understood her.

That was the poetry within Pauline: not that she was bold, not that she was odd or pretty, but that she managed to be all those things while under the thumb of the real Mr. Yang. The cold white of the mental institution had dampened her spirit, but Mary could see what remained of that spirit in the curve of her fingers as her nails tapped against the glass.

Mary wanted to make some grand gesture, perhaps lean forward and press his lips against her open palms in the hope that she would reciprocate from her side. The thought alone made him jump up in fear, effectively breaking their silence.

"How sure are you?" said Pauline, her voice hollow. She stood up with him but looked at the floor – it was now Mary who wanted her eye contact.

"You need to get the justice you deserve. Both of you. Pauline . . . " I love you. "I want you to be free."

Something flickered across Pauline – a sob, a laugh, who knew. It extinguished itself in a second.

"Who is the real Mr. Yang?"

Pauline remained silent for several moments before refusing to answer. "I belong here, Mary," she said.

Mary nodded. That was it then – he smiled at her and turned away, ready to say goodbye to Pauline forever. His one chance at a love affair was broken, but there was nothing for him to regret. He had done what any reasonable person would do and more, putting every ounce of his energy towards revisiting that one night, the only night. The woman who could have made his life meaningful. There was nothing shameful about having a cause. It was only God who decided he should die a virgin.

Besides, he still had someone to search for. The real Mr. Yang was still out there –

"And since I took his name, he goes by Yin now." Pauline's words were chased by the kind smack of her blowing a kiss.

Yes. And he would catch Yin or die trying.