Written for a challenge in /r/fanfiction: Write a story about a character who gets an earworm, combined with write a story about a rarepair.

Sam clapped the iron shackles around Rowena's tiny wrists and grinned with wholehearted satisfaction.

"What in the hell is this?!" Rowena screeched. She looked down at the shackles and chain, shook them, then glared up at him as the reality of the situation started sinking in.

"Insurance," Sam said. "Comfortable?" His eyes glittered down at her with dark amusement; he was sure the shackles were anything but was also sure that the presence of so much iron would stifle her witchery.

She drew in a shaky breath. "We had an agreement, giant!" Her voice was low and fierce, and she managed to sound shocked, as if the thought of someone reneging on a deal was outside her experience. It amused him, as he was sure that was the furthest thing from the truth. If he hadn't done this - well. It was Rowena. She'd survived centuries, set people against each other, slithering her way out of any number of bad situations. He was sure that if he had been foolish enough to trust her, she and the book and codex would have been gone in no time at all. That was probably what was fueling the anger - that he'd put a monkey wrench in her plans.

"The agreement stands. You'll decrypt the book and find me a cure for my brother. And that's all you'll get from the book." His voice was hard, the warning unmistakable. "I'll burn the book, and I'll kill Crowley. But until then..." He gestured at the chains and flicked a sardonic eyebrow up.

"I'm your slave?!" Her outrage soared. He gave her a small, lop-sided smile and turned away, ready to leave, to be near Dean and watch for any further signs of deterioration, indicators that he was falling further down into the Mark of Cain's darkness.

"You can't - you can't just leave me here!" He turned back to her, enjoying the panic in her voice.

"You want out? Hurry up. Get to work." He swung back away, striding to the doors of the filthy old warehouse, glad to actually be doing something that had a sliver of a chance at helping Dean. Behind him, he heard the sharp rattle of the chains as Rowena darted after him, and a grunt from her as she reached their limits.

"You bloody bampot!" she shouted.

He flicked a glance back, to see her grab the chains and tug fiercely at them, trying to break loose. Her long red curls flew in disarray, her fine features twisted with anger, her form-fitting black dress whirling around as she tried to free herself. It was a fine sight: Rowena, chained up, forced to do as he said.

He slapped the doors open, took a step outside, then stopped as the doors swung closed behind him, to draw a deep, shuddering breath.

It had worked. Dear God, it had worked.

Now to hope it actually produced results.

As he drove south back to the bunker, he flicked on the radio. There were three stations one could reliably get here in the hinterlands of southern Nebraska and northern Kansas: a country station, of course; a Christian music and rapture sermons station; and, if the weather was obliging, an alternative rock station from Lincoln. He adjusted the dial with long sensitive fingers and settled in for the drive. Greenday, Linkin Park, then something new he hadn't heard before. He listened absently, then snorted at the chorus.

"Somebody break these chains..."

The rest wasn't really applicable, though "I can't stand here watching you fail to tell the truth" fit with both Dean and Rowena. The crashing roar of the chorus had his heart pumping and made him grin at the memory of the witch, trapped, her eyes glittering with fury, her birdlike hands clenched into fists. He had no doubt she wanted to pummel him with those small fists for a long, long time.

By the time the chorus came around for the third time, he was singing along.

Dean glared at him from deep, brooding eyes. "You're singing. Stop."

Sam jerked his head up from the laptop and gave Dean a hangdog look. "Sorry. Can't get it out of my head."

Dean stared at him without expression for a moment, then grunted and looked back down at the books he was scouring for something, anything about the Mark of Cain. "Not like you." His face was dour, dark, and Sam's heart hurt watching him. This was the worst part of the curse of the mark, that it was leeching out the Dean he knew, turning him into a walking black cloud with a hair-trigger temper. It was only rarely that his brother peered out of those eyes at him now, and he cherished those moments. He thought back to the dinner with Charlie and Cas, when everyone had been hopeful and lighthearted, and closed his eyes for a fleeting second.

That had been when he had hidden the fact that he hadn't destroyed the Book of the Damned, but had squirreled it away, then allied with Rowena to have her search for a spell to remove the mark.

He bent his head back down to the screen and stared at it without really seeing it. Rowena. The book, the codex, chains, a deal where he would kill her son for her in exchange for a cure for Dean.

His thoughts circled around endlessly.

Dean slammed a fist down on the book he had been studying. "Goddammit! You're doing it again!" A stranger glared at him, anger flaring in his eyes, hands flexing. The air between them was charged with violence.

"Damn. Sorry." He stood up. "Look, since I can't seem to stop it, why don't I go hole up in my room for a while so I don't bother you." He flipped the laptop closed, picked it up, all the time aware of Dean's smoldering look.

A muscle jumped in Dean's jaw, and he gritted out, "Yeah. Why don't you do that?" Not even a half-hearted attempt to pass off his anger. A stranger. Sam swung away, striding out of the common room as if someone was chasing him, eager to get away from that dark, grim presence.

He bit his lips as he walked, trying his damnedest not to let his pain overwhelm him.

"Somebody break these chains - "

Rowena shot him a sour look, peering up from under her extravagant lashes, and snorted. "Not funny, Samuel," she said, holding her hands up and shaking the chain.

He had escaped from the bunker, from Dean's looming menace, with relief, offering a lame excuse for his departure. Dean had watched him go without a word, green eyes glittering and boring a hole in his back. The drive back to Kearney gave him a chance to relax, to fall back into satisfied amusement at the thought of Rowena scheming and dreaming of ways to escape.

"Sorry." Damn. That song was stuck in his head. It had fit so well with what was going on. And he couldn't stop thinking about the way her dress had conformed to the curves, the way her chest had heaved with rage, the haughty tilt of her nose, the sheer fury as she had shouted after him as he left. Which reminded him...

"So what's a 'bampot'?" He pulled a chair out from the opposite side of the table and sat down, stretching his long legs out in front of him and casting her an interested glance. She suppressed a tiny smile, as if she were happy to have said something that ate at him.

"Och, now, 'tis a very vulgar word," she said, folding her lips together primly.

He gave her a lazy look. "But what does it mean?"

She shrugged, her attention back on the books before her, curls drooping around her face. "Fuckin' idiot is, I believe, the best way to translate it," she murmured, eyes darting from book to codex, then back again, a small frown pinching her eyebrows together.

He turned to face her, leaned forward with his hands clasped together on the table. "So how goes the search?"

Her eyes flicked up to him and her frown deepened. "Bah! It goes nowhere, that is where it goes!" She slapped a hand down on the codex. "This - this - Oh, Nadia, if I could get my hands around yer neck right now!" She hissed in frustration.

He straightened up, narrowed his eyes at her, pressing his lips together. This didn't sound good. "What d'you mean? Remember, the longer you take, the more time you spend in those." He tilted his head toward the shackles.

"Aye, well, I'd be more than happy to get this done, as soon as possible! But Nadia, that bitch, went and coded the codex!" Her voice rose. She stood up and slammed both fists down, chains rattling, one fist on the codex, one on the Book of the Damned. She leaned forward over them, angry eyes focused on him.

Equally angry, he stood up, too, planted his hands on the table and leaned forward until his face was inches from her. "So help me God, Rowena, if this is some excuse - !"

She tossed her head, curls tumbling down her back, and looked down her slender nose at him. "Oh, aye, of course, 'tis some wicked scheme on my part! Bloody idiot!"

He ground his teeth, then seized her shoulders to shake her. "I wouldn't put it past you!" Her head bobbed back and forth with each shake, until she grabbed his forearms to stop him and steady herself. He couldn't help noticing how close she was, how wide her pupils were with anger, her delicate scent, her nostrils flaring.

Her lips peeled back in a grimace to bare her teeth. "If you had what few wits God grants to little children and idiots, you would realize that doin' that keeps me in these that much longer!" She let go of his arms and held her hands up between them, shaking them so the shackles and chains jingled softly. The sound made the song that had been haunting him tumble to the surface of his mind again and he shook his head sharply to try and dislodge it. Rowena took that as a negation of what she had to say. Before he realized it, two dainty hands had gripped the sides of his face, the chain between them dipping below his chin, and she was snarling into it, "D'you think I want that?!"

The earworm was too much to explain. Besides, all of a sudden he knew what he wanted, and the knowledge rocked him to the point of not being able to say anything. So he just shook his head wordlessly, hoping she wouldn't see what had flashed into his mind, hoping he could make it go away with the earworm.

The hands stayed on his jawline, the long fingernails poking into his skin, as she glared at him from inches away and huffed with anger. As he stood there without saying a word, her huffing slowed, her fingers relaxed, but as she calmed, she didn't move her hands. Though she was the one in chains, he felt trapped. He carefully focused over her shoulder, but was aware of every movement she made, his skin tingling at her nearness.

Damn. Always go for the 'bad girls', don't you? Now what?

"Well. Now that we've vented some steam, back to work for me, giant." Her voice was quiet, murmurous, and she gave him a gentle pat on the cheek. He could see, from the corner of his eyes, that she had a faintly speculative look, one eyebrow tilted. She shifted back, away from him, straightening up and stretching. Her form-fitting black dress stretched with the movement, outlining the curves of her body. He clenched his teeth and swallowed.

"See that you do," he said, voice tight.

Without another word, he spun around and walked to the door. She watched him, then called out, "Oi! Find me a code-breaker, Samuel!"

A code to break the code. He thought about it on the drive back to the bunker, in between flashes of Rowena's trim body and snatches of the song. As he pulled up to the bunker's hulking presence, his brain finally decided to kick into gear.

"Charlie!"

She was a hacker, a computer code breaker. She figured out ways to hack into a wide variety of systems. The codex was just that: another system.

He pulled out his phone, texted her for a meet-up, and slung his legs out of the car, thoughts refreshed.

If Charlie's there...no way to act on my...thing...with Rowena.

Cracking a relieved smile, he ran down the steps to the bunker door, heart lighter than it had been in days.

It had been a good idea. Bring Charlie in on the plan to break the various codes, get a spell to cure Dean, and all would be well with the world.

Then it all came crashing down. Eldon Styne in chains in the bunker dungeon. Dean interrogating him, then coming back out into the common room with the knowledge that the book had not been destroyed, circling Sam like a shark, eyes dark and suspicious. Styne escaping. Charlie disappearing.

As he carried dead branches to the Hunter's pyre for Charlie, the song rang in his head again. Chains. Somebody please break these chains that are binding me into this shit show.

He couldn't cry, couldn't weep for her, not with the knowledge that it was his fault. All his fault. More branches. Charlie wouldn't have been so desperate to break that code if she hadn't been cajoled by him. Another armful. If he hadn't called her in...if he hadn't cooped her up with Rowena - fire and water, opposing personalities. If she hadn't been desperate for the quiet she needed to focus on breaking the code. Still more branches. She wouldn't have been in that sleazy motel, all alone, if it weren't for him.

Dean worked with him, building the pyre, grimly silent, radiating bitter anger and pent-up violence.

Sam laid Charlie's body on the pyre and mouthed some meaningless words while the song thundered in his head and the guilt pounded in his heart. He watched the flames as they rose. When Dean turned on him, hit him with the words that he should be the one on the pyre, not Charlie, he stood there listening and barely even flinched, because he knew Dean was right.

The only thing that pierced the fog surrounding him was Dean's vow of vengeance on the Stynes as he strode away. He looked after his brother and saw, not Dean, but the stranger again.

He had that thirst for vengeance too. But Dean was heading in the wrong direction, so far as he was concerned, because that vengeance should be aimed squarely at one Sam Winchester.

He trudged to his car alone, climbed into it, glanced at his laptop with the downloaded file from Charlie that contained the broken code. He closed his eyes in pain, then re-opened them, gritted his teeth, and sent a quick text to Cas, alerting him to Dean's plans of vengeance. Then, sighing, shoulder slumped, he started the drive to Kearney. Time to give Rowena the final ingredient to find that spell.

He opened the door to the warehouse, hinges creaking loudly and echoing in the dusty silence. The last time he had been here...persuading Cas and Charlie to join him. Both of them dubious at the plan. Rowena, in a comic stage whisper, saying to Cas, "The first rule is, don't tell your brother what we're doin'!"

He ground his teeth, flexed a hand into a fist, thumped it against his thigh. Looking around, he saw no-one.

No-one?!

Where the hell was Rowena?!

"Helloooooo?! Out there! Is that you, Castiel? Let me out of this room!" Her Scots lilt was muffled, and her words were accompanied by banging on a door to his right. He folded his lips together, strode over, and yanked it open. Rowena, who had been leaning against the door while hitting it, tumbled forward with a clatter and clank of her chains. He automatically grabbed her to steady her; her hands clutched at his arms at the same time.

"Samuel! Thank heavens. I've been cooped up in that remnant of a brewery for days! Do be a good lad and settle me back by the table. I assume that your precious tech queen has cracked the code since that angel sequestered me?" Her tone was haughty, her fine nose turned up, her shrewd eyes darting around the echoing spaces of the main warehouse room.

'Precious tech queen' - ! Charlie - !

He snarled and scanned the room behind her, searching for where Cas had fastened her chains. When he located it, he strode over, unlocked it, and strode back to Rowena, reeling in the chain as he went. When he reached her, he didn't stop, merely yanked her along with him. She stumbled behind him, holding onto the chains to steady herself.

"Oi! Samuel! No need to be naffy here!"

He thrust her down into the chair, then spun away to re-attach the chains. Then he dropped the laptop before her, flipped it open to the code file, and rapped his knuckles on the table beside it.

"Here's your translation. Get to work." He started to leave, but Rowena reached out and clamped a firm hand around his wrist, holding him back.

"Not before y'tell me what's amiss, boyo." Sharp, shrewd green eyes, framed by ridiculously long eyelashes and decorated with cats-eye make-up, peered at him. "Where's the angel? Where's Charlotte?"

He broke. "Charlie!" he shouted, rage rising to fill him. "Her name was Charlie, dammit! You don't know her, don't have any right to mangle her name - " His voice cracked and he stopped, chest heaving, a muscle jumping beside his jaw.

Rowena leaned back in her chair, her free hand tucked beneath her chin. "Ahhh. So. As I told her: her love for you and your brother would prove her undoing." He snarled at her, angry at the assumption. She tugged at his wrist. "Sit. Tell me the tale, giant." The pain flared through him again. He closed his eyes against it, crumpled into the seat, began a toneless recitation of the bare facts. Each part of the story was another stab in the gut, another self-accusation of guilt. She let her hand lie gently on his wrist, saying nothing, just watching and listening.

As he went on, he spoke slower and slower, mouth dry, heart heavy. He finished and sat for a minute staring blindly at the back wall of the warehouse, seeing how it must have gone down in his mind. "My fault. All of it," he finally croaked.

At that, Rowena sniffed and threw her hands up between them to stop him. "Och! Spare me the insipid guilt and self-flagellation!" Startled out of his contemplation, his eyes flew to her, and he opened his mouth to proclaim his fault. But she leaned forward, clapping her hand over his lips, her eyes angry. "Aye, and I'm sure you ferried her direct to that hotel! And led that scion of the Stynes to her, opened the door for him, said 'Have at her'!" He frowned and shook his head slightly, confused at how she was twisting it.

"She would never have been there if it wasn't for me!"

Rowena's lips twisted. "Oh, and an easily-led lass our Charlie was, for sure!" she said, sarcasm dripping from her voice. She snorted, and his frown deepened.

"Of course not! What - ?!"

Rowena stood up abruptly and began pacing, rigid with anger, her skirts swirling around her ankles as she turned to him and shook an admonishing finger. "Well, from what I could see, that isn't the Charlie I knew! The Charlie I knew was a bright young woman, swift-thinking, sure of herself. She did what you asked out of 'love' - " She sneered the word. "Oh, yes, but 'twas her choice, not yours! She was intrigued and challenged by that task of breakin' the code, she wanted to do it! She made her own choices and stood by them, and I will be damned if I'll let you sit there and whine and pule about how it was your own fault, as if she had nary a say in the matter! The world does not revolve around you Winchester boys, and people are not mindless chess pieces that the two of you push around! I liked that girl - she would have made a fine witch! - and I will not let y'wallow in self-indulgent guilt that negates all her choices!" She finished her tirade leaning over him, fists resting on the chair arms on either side of him, eyes flashing, and a scornful twist to her lips.

Sam blinked at her ferocity, opened his mouth, thought a moment, and closed it again. Rowena nodded fiercely. "Aye, you just stow that gab of yours and think for a wee bit about your friend, your 'little sister', and how she might want to be remembered!" She paused, huffing, then added with a sneer, "Bloody heroes!" Her Scots accent and scorn turned the word "heroes" into an epithet.

"But - but - " She had twisted it all around, he thought in a daze. How could she make it sound like him feeling guilty was - was selfish?!

She leaned even further into his face and hissed, "'But' nothing! 'Tis always so! A woman makes choices - her own bloody choices! - and the men around her refuse to let her choices stand, must always be takin' the credit - or the blame!" As if driven, she grabbed his shoulders and shook him, emitting a frustrated, angry sound like a tea-kettle. "Ooooh! And men who fancy themselves 'heroes' are the worst of the lot!" she shouted.

"We're not heroes!" he shouted back, frustrated, putting his hands on hers to stop the shaking.

"Oh, now, are y'not?" she purred at him. "Rescuin' people, killin' the wee monsters, tryin' to save the world and making a right mess of it, as far as I can tell!" She arched her eyebrows at him with a tiny simper.

Again, he opened his mouth to refute her, and again he found himself at a loss. "We...we just want to help people," he finally said. She rolled her eyes. "And...and...no matter what, no matter whose fault, Charlie's dead." He paused, wet his lips, and whispered, "And that...hurts." She pulled one hand away from his shoulders and tapped him on the cheek with a small, wry smile.

"Aye. I can see that. But I can also see that I've gotten you to think, instead of wallowin', which is better in the long run, eh?" She had. It was. He ducked his cheek against her hand, closed his eyes.

"Thank you." It was hard to say, especially to someone he would normally consider an enemy. Wanting her, being attracted to her, was one thing. But this was something else, true gratitude for helping him see the whole mess of the past few days in a different light.

"Ach, well," she murmured, her hand cupping his cheek. "I did not like seein' you like that, all twisted up in yourself. All you needed was a little shouting at, a wee distraction." Without warning, she swooped in towards him, hair tumbling around them like a veil, and whispered in his ear, "Though I can think of more amusin' distractions!" She pulled back a bit, gave him a mischievous grin and a wink, and then placed her lips on his, soft and warm and gentle.

For a moment, he was too startled to do anything in response. She drew back, cocked an eyebrow at him, and shrugged. "Eh. 'Twas just a passin' thought."

"No - wait - !" He reached for her, twisted his hands in those glorious red curls, pulled her head back down to his. Where her kiss had been soft and gentle, his was anything but: hard, demanding, passionate. When her lips opened beneath his, he groaned against her, slid an arm around her trim waist, pulled her down into his lap. She smelled of citrus and tasted of wild moors and sea breezes and her small, elegant body molded against his in a very satisfying way. Her hands were busy unbuttoning his flannel shirt, sliding up and down his chest, and she giggled softly.

"Hmm?" he murmured around the skin on her neck, which he was exploring with his mouth.

"Ohhh, just thinking of a conversation I had with someone about firm bodies. Yours is definitely..." She paused and pressed her hand against his chest. "Very firm." She chuckled again, and returned to her work. When she had the buttons all undone, he let her go so she could shuck the shirt and pull his henley beneath it off. He shivered at the touch of her hands on his bare skin, and with a quick movement, stood up, carrying her over to the mattress he had provided her days ago when he had first brought her here to work on finding the spell.

He placed her gently down, standing before him, and turned her so he could get to the zipper on her dress. A slow and tantalizing pull downwards, and then his hands were on her shoulders, sliding the fabric off and down her arms. The dress fell into a puddle of fabric on the floor, and she stood before him, alabaster skin glowing in the dim, fragmented light, her red hair contrasting vividly. She leaned into him, humming, nimble fingers busy with his jeans, and then they were falling to the mattress, buried in their exploration of each other.

The buzzing of his phone woke him to the faint morning light. He groped for the phone, pulled it toward him, cracked an eye open to look at it.

Cas.

Dean was on his way to Louisiana, to the Stynes' stronghold. Sam closed his eyes, the reality of Dean's situation crashing down on him again.

Somebody break these chains...

With a sigh, he sat up, pulling his jeans and undies close, and began dressing. The sound woke Rowena, who lay blinking up at him when he stood, lips twisted in a wry smile.

"So, giant. Off again?"

He smiled back down at her, then swooped down and kissed her. "Dean," he said, as if the name was explanation in itself. She snorted softly.

"Aye. Of course. Well, then, get you goin'." She flapped her hands at him and stood, stretching luxuriously. The morning sun outlined her silhouette, making his groin clench with renewed desire. But...Dean. The Stynes. He made a wordless gesture, trying to think of what to say. She snorted again. "'Twas a fine, fun distraction, Samuel. Perhaps another time?" She arched an inquiring eyebrow. He shrugged helplessly. "Go to your brother. Go on, now!" He dithered for a second, and she flapped her hands again. "Shoo! I have work to do!" She bent down with a dancer's grave to scoop up her dress.

He sighed and turned away, striding to the door with a pause to grab his henley and flannel shirt and pull them on.

Then he was on the road back to Lebanon and the bunker and his desperate hope that Dean wouldn't get himself killed, wouldn't end up killing too many people to slake both his thirst for vengeance and the blood lust of the Mark of Cain.

A/N: the song that gets stuck in Sam's head is "In Chains", by Shaman's Harvest