A/N: I'm very excited to begin an obsession with a new fandom! The Flash! Oh Netflix, you devil...I'm almost caught up-to-date. Snowells is my new fav OTP. Don't care what direction the show moves into - I'm very happy with my own corner of augmented reality - where Snowells is canon. ^^

Caitlin stifled a sigh and kept her smile in place for Iris, nodding as the other woman read off every item of the Halloween party list they'd both worked on last week. Impressed with the amount finished, but anxious to get back to work, Caitlin had stopped actively listening. She gave an occasional 'hmm' or 'okay' in acknowledgment only to be brought back to earth when Iris became super excited. What the hell had she agreed to?

"I knew you'd be the one to make sure Dr. Wells comes and wears a costume!" Iris clapped her hands and closed her notebook. "I gotta go talk Barry out of us dressing up as Superman and Supergirl."

Despite herself, Caitlin giggled. "His heart is in the right place at least."

Iris rolled her eyes. "We don't need any more reminders we were basically raised as siblings."

"Good luck!" Caitlin waved goodbye to Iris and wished for her own mega-sized portion of luck; getting Harry to attend and wear a costume was going to be an uphill battle. Well, no time like the present to distract and attack. Guilt, would that work on her favourite grumpy scientist? Ah, no matter. If all else failed, she'd go quiet and sad - that ought to bring him 'round to her wishes.

Knocking softly on Harry's lab door, Caitlin waited almost a full minute before slowly letting herself into his lair. He might be engrossed in an experiment or tweaking a piece of tech, but Cait knew he'd allow her inside. But it was his lair, his lab was his first home - and if he wasn't here, then she'd just hunt him down to his actual set of quarters.

Empty.

No Harry, no machines busy with esoteric tasks, no activity save one Caitlin Snow walking the perimeter, checking for her own interest the last experiment Harry had been enthusing about.

Plan B then, perhaps Harry was already holed up for the night in his set of rooms. Caitlin couldn't stop herself from letting her fingers caress the stack of books to the right of the computer station. The top tome fell and she hurried to pick it off the floor. Always curious, Cait opened it and flipped through. It was one she'd recommended to Harry - not even two days ago. Interesting.

This time, surer of finding Harry, Caitlin knocked with confidence, loud and authoritative; as if her alter ego Killer Frost was telling Harry she was there. No meek miss asking for entrance -rather, telling the occupant there was company to be had. The idea had her grinning and as Harry opened the door, it was her grin that Harry reacted to first.

"Good news?"

"Yes?"

"I'm thinking, no." Despite the negative words, Harry's tone wasn't - he was curious about exactly why the woman he'd been thinking about had shown up on his doorstep. Reality gave him a hard slap and Harry sucked air over his teeth. This had to be a trick or something else - something unpleasant. Caitlin was a delight, but the universe wasn't in the habit of giving him presents. "Come in, you're letting the warm air out." He smirked. Of course, that was a lie, but it suited his sense of humour.

"Thank you." Ever the polite and attentive guest, Caitlin hurried over the threshold and shut the door. "I hope I haven't interrupted you doing anything important." She let her eyes dance over everything she saw - she'd been wanting to visit his rooms for the longest time, but she'd never had a good excuse. Today though, she had a reason. Caitlin smiled. "I've come to help you!"

Taken aback, Harry almost dropped the book he was holding. Snow couldn't know of his personal plans; the lubricant waiting in his shower, could she? No, of course not, it was just wishful thinking. "With what?"

"As you know, Team Flash agreed to throw a Halloween party for the fine citizens of Central City in the environs of STAR labs." Caitlin could feel her natural enthusiasm rise to the occasion. "It's my pleasure to assist you with deciding on a costume and attending!"

Harry wondered briefly if he'd become senile. Snow was prattling about a Halloween party? "I'm far too old to play dress-up."

"Don't be such a party pooper, mister!"

"It's doctor, Dr. Snow."

Caitlin gave a rueful smile at the snide comment. "Noted." She chewed her lips and tried to jam her hands into non-existent pockets on her skirt. "It would mean a lot to the team if you showed up and joined us."

"I have experiments to plan and more important issues to take care of than helping inspire the plebian public to feel any sort of indebtedness towards even this Earth's STAR labs." Harry winced as Snow blanched. "Not that it isn't a worthy effort…"

"No, I understand." Caitlin looked at her feet and mentally girded her loins. Resolute, she moved further into Harry's room - closer to his rumpled bed. She'd pegged him as a ship-shape type of man. If he wasn't in bed it should have been pristine. Covers smooth and pillows arranged with military precision. What an odd random thought. Back to the matter at hand. "You're afraid."

Incredulous, Harry did drop the book he'd been cradling. "Don't be ridiculous. Me? Afraid? Of what?"

"Having fun, relating to people, not being a grump, and having fun," Caitlin rejoined quickly. "You're especially scared of having fun. You don't have to pay for your mistakes until the end of time - we know you're a solid member of the team. We all want you to be there. You deserve to have fun."

Harry stared at Snow - such a lady, but right now spitting fire and ire as if that would be enough to bow him to her will. "Crowds aren't fun. Costumes and stupid heathenish rites aren't fun. Halloween is a waste of time."

"You're wrong!" Cait actually stomped her foot. "It's a chance to hide your regular self and have fun exploring any avenue of behaviour you want."

"Oh?" The timbre of Harry's voice dropped.

Caitlin felt the hairs on her arms stand to attention; that raspy voice was sinfully sexy. Without considering her words further, Caitlin said, "A costume is both armour against the world and expression of one's deepest self."

"Unless it's one of those sexy, mass-marketed costumes," said Harry drily, "then it's all about making money from a postage sized scrap of fabric. The people who buy those are foolish, deluded souls."

Aghast at Harry's cruel words, Caitlin blinked and stood frozen. A sharp look entered her eyes. "I bet I can prove you wrong." Not letting Harry speak, Caitlin strode over to him and poked him in the chest. "Why don't you wear a sexy costume and I'll wear something that matches you, but innocent. You stay at the party until I give you permission to leave and I'll -"

"Do whatever I demand?"

"Yes!" Caught up in the moment, Caitlin agreed. "Doesn't matter what! Any of your experiments at all! Whatever you want - I will deliver."

"I accept."

"Y-y-you do? I mean, good!"

"Meet me here tomorrow night and we'll discuss your half of our couple's costume." Harry inwardly screamed. Heaven and hell; both god and the devil had to be laughing. Snow was too innocent even with Killer Frost's influence. "Even as excellent an experiment partner as you are, I may not require that as my fee."

Resolute, Caitlin shook her head. "Doesn't matter. I know you won't take advantage, I'm not scared of you."

Caitlin nodded dumbly. Harry had just told her his costume and it was indeed sexy. There were few things that revved her engine as much as a man in a fine suit - and to whit, Harry, in an immaculately tailored suit, even garnished with horns, tail, and pitch-fork... That was a recipe for a perfect lust storm.

"-You'll be my Snow Angel of course." Taking it for granted, Harry smirked, arms crossed. "Covered from neck to toes, you'll be pure and pristine to match my evil and loathsome attitude."

"Much like beauty is in the eye of the beholder, so must be evil." Caitlin snapped back her rejoinder and stood defiant in front of Harry. "Even angels fall." She flushed but refused to retract any of her words. "Be ready to have fun Friday night dammit!"

Head held high, Caitlin stomped out of Harry's private set of rooms.

Loud music and a steady stream of guests entering and winding about the decorated rooms of STAR labs had most of Team Flash excited. Cisco's spirits were high and only getting higher while Joe pessimistically lamented the chances of criminal activity only spiking. Iris and Barry held hands and gazes. Wally rolled his eyes. Jesse tugged the neckline of her costume higher - suddenly freezing as the last two members of Team Flash entered the designated main party room of STAR labs.

"Lookin' fine you two!" Iris jumped in excitement. "You do know most people dress opposite to people's expectations?"

Barry snorted and then looked immediately apologetic. "Oh, I bet lots of people who don't know Dr. Wells wouldn't think of him as Satan."

"Yeah," Cisco gave Barry the 'okay' symbol, "only the people who don't know he's a dick might think he's unsuited to be the devil." In response to Caitlin's moue of dismay, Cisco made an overblown bow and took her hand. "You make a lovely angel."

"A snow angel, dolt." Harry took pleasure in being even more blunt than usual. "She's obviously a snow angel. Look at her voluminous and icy white gown, snowflakes on her cape and icicle halo." Tossing his own red satin cape over his shoulder, Harry gazed coolly at his co-workers. "You'll be lucky if tonight doesn't bite you all in the ass."

"Good talk!" shouted Cisco as Harry dragged Caitlin towards one of the refreshment tables. Cisco cupped his hands around his mouth and continued to sass Harry. "Remind me never to use the phrase 'bite me' with you." Cisco exchanged high-fives with the rest of his team. "Stage one, complete."

"Thank you." Caitlin accepted a cup of mystery punch and tentatively sipped. It was boozy but sweet and therefore pretty good. "This is nice, isn't it?"

Harry scowled. "Has the definition of nice been changed? I hate crowds and I dislike them more when they're drunk and disorderly."

A man wearing a Captain Marvel costume stumbled into Harry and reached out to steady himself on Caitlin's shoulders. "Ooh, an angel!"

Harry gave the man an evil look. "Keep your hands off the snow angel. If you can't handle your drinks, you ought not be drinking." He detached the offending fingers and glared. "Go away."

"Way to keep in character dude!" Drunk Captain America clapped his hands and smiled lopsidedly. "I'd keep my wife safe too - if I had one!" He laughed as if he'd delivered the wittiest joke. "I gotta go find my own Peggy Carter and Bucky." As fast as he'd interrupted, the stranger staggered away, disappearing into the partying crowd.

"My hero."

"Only you, Snow, would ever have the brass tacks to say that like you meant it." Harry looked down and away before draping Caitlin's free hand into the crook of his arm. "I should keep you close. There's a lot more drunk idiots who might accost you."

"I'll allow it." Caitlin looked at Harry from under her lashes. She wanted to say so much more. Something like, 'I'd rather be with you than without.' God have mercy, how strong had the punch been?

"Excellent." Despite himself, Harry's grin was warm; Caitlin had the ability to rev his engines and soothe. "Hungry?"

"Not just yet." Caitlin giggled. "I was thinking about drinking more before dulling any alcoholic haze with food."

"Then let's indulge."

Caitlin shivered. Harry might not have intended to sound like pure carnality - but he had. Indulge? Oh, there were so many things that Caitlin wanted to do and have done to her. Instead of pouring out her dark desires, Caitlin nodded then drained her cup of punch. "Let's get some real drinks."

Cisco adjusted his turban. "The amazing Carnac votes we go to the karaoke room!"

"Really?" Joe breathed even heavier into his Vader mask. It was hella fun, making his speech into the notable sound of James Earl Jones. "Make it so, number one."

"Wrong!" Iris shook her head. "Dad! You're mixing up Star Wars and Star Trek!"

"Yeah, 'fraid so, Joe!" Barry flipped his Iron Man mask up to look with worry at his foster father - slash - soon-to-be father-in-law. "Can't you keep D.C. and Marvel separate?"

"Tch! Star Trek is Paramount!"

"Then what am I confusing with D.C.?"

Several voices shouted and began arguing with immense fervour.

Several shots of tequila later, Caitlin smiled at Harry. He'd kept the worst of the drunken revellers from her as well as staying right next to her side. This might be the best day of the year as far as Caitlin was concerned. Nothing else could compare with being escorted by a tall and handsome devil. Caitlin snorted sudden laughter.

"What's got you amused?"

Harry's gravelly tone stoked Caitlin's hormones.

Harry scowled, but his deep blue eyes betrayed his curiosity. "What else do you need?"

"Don't ask something like that if you don't want an honest answer." Caitlin reached up to adjust her icicle halo. "And before you say anything else, I do understand the difference between need and want."

"Of course." Harry masked his sudden confusion by withdrawing the red silk handkerchief from his suit pocket, tucking it back with more care. "I've always been impressed with your intelligence, Snow. You're remarkable."

"Maybe it's the drinks talking, but why don't you call me your Snow Angel?"

Harry wanted to say so much but settled for a quick nod. There were worse things Caitlin could have asked of him. Sidestepping her last question, Harry decided to guide her back to the bar area. "How's about a few more drinks?"

"Such a naughty, handsome devil. Trying to get me drunk and take advantage? I mean, way to get into the festive feel tonight!"

"If only you were my Snow Angel," Harry muttered this louder than he'd intended - making Caitlin clutch his arm and stand still.

"Are you going to give me a Christmas miracle gift on Halloween?"

"We're both a bit drunk. I don't know what you mean." Harry made the mistake of looking into Caitlin's eyes. Warmth rocketed from the pit of his stomach. "What sort of gift were you wanting?"

"Honesty would be a great start."

"Well, I honestly think I've attended this party long enough," Harry smirked. "I know you like to keep a clean slate. You up for your end of our bargain?"

"More than you know." Caitlin raised her chin. "Let's blow this popsicle stand."

And very much like a Christmas miracle, the crowd had parted for both Harry and Caitlin; the escape to his private set of rooms at Star Labs was quick and uneventful.

Closing the door, Harry dropped his pitchfork and detached the cheap red horns of his costume. "Ahhhh."

"Not to be rude, but I kind of liked the horns." Caitlin removed her halo, holding onto it with twisting hands. "They didn't look wrong."

"Thanks." Harry drew out the 'ess'. "Your halo - I'd imagine a flower crown would be the only thing to suit you more."

Touched by his sincerity, Caitlin blushed. "What's with the compliments?"

"That's actually tied in with our little wager." Harry stalked further inside his rooms, jamming his hands into his pants pockets. "You've agreed to anything I demand - and even dressed as the devil, I can't imagine forcing my true wants."

"Which is why it was so easy to agree to your demands." Caitlin flopped onto Harry's bed in a boneless display. "I know you and you're much kinder and sweeter than you present yourself." She kicked off her shoes and giggled as they made a god-awful racket. "You're not even close to devil-status, Harry."

"I might be afraid to do the thing I want, but it remains the thing I want."

The sincerity in Harry's voice made Caitlin sit still. Her intellect, only slightly slowed and addled by tonight's alcohol made sense of his words. "I freely agreed to your terms."

"That you did." Wonderment glowed in Harry's eyes. "Are you sure?"

"Are you?"

Harry stalked closer, grinning as he pinned Caitlin to the side of his bed. "What I want is your active participation. If you can't join me, then there's no point."

"Didn't I tell you earlier that even angels can fall?" Caitlin licked her lips. "I'm no angel for all that everyone seems to believe that." She kept smiling at Harry. "Why don't you elaborate exactly what you want?"

"Lots of heat, sweat, and passion." Harry swooped in, connecting his lips to Caitlin's - delving his tongue deep, coaxing a moan from his Snow Angel's lips. Harry plunged his fingers into Caitlin's hair, closing his eyes as he deepened his kiss. He slanted his mouth and panted harshly.

Long minutes passed as the couple writhed on the bed. For her part, Caitlin could only react with delight - and Harry poured his considerable ardour into their lip-lock. Harry groaned, lifting his weight from Snow's body. "This is moving rather fast. I, ah, you don't have to stay."

"I know. I want to be here. Now, let's get rid of these clothes." Caitlin slid her hand from Harry's hair onto his chest and deftly popped several buttons of his dress shirt. "They're cramping my style."

"We can't have that."

"Not when we can have the heat, sweat, and passion you mentioned earlier." Caitlin smiled up at Harry and winked. "Don't hold back." She ripped Harry's shirt open the rest of the way. "This Snow Angel is very inspired by her personal handsome devil."