"Oh, it's just - I don't need you anymore. I mean, Dean's the one with the link to Amara, why have I been trying to spare you?" Cas's rumbling tones had gone and Sam felt a chill down his spine. He knew the voice that was speaking now only too well. "I mean maybe it's because you're like the girl who kept turning me down at the prom." He grabbed Sam and slammed him against a column, forcing all the air out of Sam's lungs.

"I will touch your soul," the angel said in that same light, vicious tone. "Just because you asked so nicely, and I'll use your spell to blast through the warding and retrieve Dean and the uh, Hand of God, and then when Dean comes back and he finds this place decorated with your guts, I will tell him the truth, Sam. I'll just say, 'Dean - ' He paused and smiled before dropping his voice back into Cas's deeper registers. " 'Dean… he knew the risks. He wouldn't take no for an answer.'"

"Lucifer," Sam breathed. Lucifer looked delighted.

"In the flesh," he agreed. He pressed his body against Sam's. Cas's body. Sam shuddered in revulsion and horror. Lucifer leaned forward, his face close to Sam's and he placed a gentle kiss on Sam's lips. Sam struggled uselessly, turning his head away.

"Sam," Lucifer said. "Come on. I know you want to."

"No!" Sam yelled. Lucifer regarded him for a moment then gave a heavy sigh. He laid his hand against Sam's chest and began to shove inside to find Sam's soul. The pain was unimaginable and Sam screamed in agony. Lucifer's face was ecstatic.

"Oh, Sam" he breathed. He tucked his head into Sam's neck and scraped his teeth over the sensitive skin there and Sam's shivered in revulsion. "You feel so good," Lucifer said and he lifted his head. Suddenly, his expression twisted and he pulled his hand away. Sam slumped to the ground and everything went black.

As Sam lay on the floor, slowly regaining his senses, his head was spinning. Lucifer! What the Hell was going on? He carefully sat up as Cas's body toppled to the floor beside him. Unnerved, Sam scrambled away as best he could.

"No, no!"

"Sam, it's me," Cas said with obvious effort.

"Cas?" Sam said, even more confused. "Why?"

"I wanted to be of service to the fight. And only Lucifer can beat her." He was breathing hard, as if every word was a struggle to speak.

Sam stared at the angel, utterly appalled. "You chose this? You have to fight, Cas! Eject him now!"

"I can't!" Cas grunted, shaking his head. "It's taking all my strength to keep him from killing you. And besides, we need him!"

"No Cas, we don't." Sam denied. "We'll find another way to stop Amara!"

"We need him to save Dean," Cas insisted.

Sam sighed as realization dawned. "You can't time travel."

Cas shook his head again. "Only Lucifer can." He closed his eyes and there was a sudden agonized look before Lucifer's sneering expression returned.

"It seems Castiel would very much like me to rescue your brother," he told Sam. "And right now, he's making it difficult for me to kill you." He gave a big sigh, looking very put out. "Fine." He pulled himself to his feet and stared down at Sam. "Maybe he's right." And with that perplexing statement, he disappeared.

Dean felt Cas's hand fall on his shoulder and the next thing he knew he was back in the bunker. Sam was lying on the floor and Dean stared at him, puzzled.

"Dean -" Sam barked. "THAT'S NOT CAS!" Dean gaped at him for a moment and then turned slowly to look at the angel who looked both sheepish and gleeful.

"Cat's out!" he said in amusement and grabbed Dean, throwing him across the table. Dean's brain had completely short-circuited. "I feel a burden lifted. You know, this whole - deep cover thing - it just wasn't - it wasn't terribly well thought out. Donning this - this Cas mask?" Lucifer? Dean's insides twisted in shock. Oh, no. No, no, fuck no! Lucifer continued monologuing at him. "This grim face of angelic constipation? It just - ugh. And then, teaming up with you two. I mean, I thought you boys were insufferable as mortal enemies, but working with you. That's the soul crusher." Dean struggled to get to his feet and behind C-Lucifer, he could see Sam pulling out a knife and cutting his hand. Lucifer made a careless gesture and pinned Dean against the wall with his power.

How long had Lucifer been keeping up this charade, Dean wondered in horror. Who exactly had he slept with on Valentine's night? He felt sick. That had been after they'd returned from Hell.

"Why the faces, boys? You should be cheering," Lucifer continued. Dean tried to suppress the appalling emotions within him and watched as Sam painted the angel-banishment sigil with his blood on the wall behind him "We have a common enemy. With this," Lucifer brandished the Hand of God Dean had brought back from the USS Bluefin, still wrapped in cloth. "She will be no problem. I mean, I will have killed you both by then, but still. Come on." Lucifer flashed Dean a grin and then unwrapped the Hand of God.

"No!" Dean yelled. Lucifer placed his hand on the Hand of God and then turned it over in his hand. "NO!" Lucifer ignored him and closed his eyes, his face expectant. After a moment, he frowned. Dean stared at him. What was going on? He flicked his eyes back to Sam, who was almost finished. He looked back at Lucifer.

"It's kicked!" Lucifer snarled.

Relief washed over Dean. "Well. Who'd've thought the Hand of God would turn out to be a one-hitter?" he said. Lucifer tossed the useless object onto the table and advanced on Dean, his face menacing. Sam slapped his hand against the sigil and with a flash of light, and a shriek of rage, Lucifer was gone. Dean exchanged a look with his brother and collapsed to the floor.

Dean was slumped over the library table. Two empty bourbon bottles and no fewer than a dozen beer bottles were scattered over the surface. Oh shit, Dean had really gone all in this time. He was snoring gently and drooling on the table. Lovely. Sam laid one hand on Dean's shoulder and his brother startled rather dramatically, almost falling out of his chair.

"Sam! It's you," he said unnecessarily.

"Uh, yeah," Sam said carefully. This was fucking awful. This was worse than fucking awful. Dean was a mess. And with good reason, Sam admitted to himself. Even without the added burden of his brother's Valentine's Day activities, the revelation that Cas had allowed himself to be possessed by Lucifer was almost too much for Sam to bear. His skin crawled at the thought of the archangel creeping around the Bunker while he and Dean slept. The moment the Cas mask had slipped and Lucifer in all his terrible viciousness had smiled at him wearing Cas' face, had made him want to vomit and howl and scream at the sky. How Dean must feel, Sam couldn't even imagine. What had Lucifer wanted? Why take Dean to bed like that? It wasn't that Lucifer was a prude, far from it. But he'd always seemed fixated on Sam. Had Sam's refusal to host him again finally turned Lucifer's attentions elsewhere? Did that mean he wanted Dean now or was it a side effect of possessing Cas? It seemed unlikely. More probably, this was some level of mind-fuck. On Cas, or Dean or maybe both of them. That Sam could easily believe.

What the Hell were they going to do? It had been bad enough when they only had Amara to deal with. Now Lucifer was free to unleash whatever alternative Apocalypse he could imagine on the world, and it was Cas of all people who was responsible. Fuck, fuck, fuck. Sam squeezed his eyes shut for a moment, pain thudding along his nerve-endings.

"Sam?" A concerned voice sounded in his head. "Sammy, what's wrong?"

"Gabriel?" Oh, no. Not now. Not on top of everything else.

"Yeah, kiddo. What's happened? I can feel your distress from here." Gabriel's voice was strangely soothing.

"Something bad. Where are you?"

"I'll be with you as soon as I can. Hold tight." He shouldn't feel relief that Gabriel was coming. Spending time with the archangel was going to hurt. But the tension in his head relaxed and he gave a grateful sigh.

Gabriel eyed the unconscious Dean on the table for a moment. He did not look amused.

"Castiel invited Lucifer into his vessel?" he said again, sounding almost dazed. "I guess his induction into the Winchester family is complete."
"What's that supposed to mean?" Sam snapped. Gabriel was not taking this news very well, which he figured was only to be expected.

"Self-sacrificing idiocy and a woeful lack of self-worth," the archangel said archly, one eyebrow canted at Sam. "Do I have to do everything myself?"

"Hey," Sam said, wounded. "It's not my fault." Except it was of course. If he hadn't gone haring off to Hell with Rowena and Crowley, Lucifer wouldn't have had a chance to tempt Cas into saying yes.

"I wonder what my brother said to Castiel to make him agree," Gabriel mused and Sam couldn't help but think it might be Dean's fault. Gabriel's other eyebrow rose to meet the first one. Sam really needed to remember the archangel could read his mind.

"Look, Cas and Dean's relationship is complicated," Sam tried to explain. Gabriel laughed, a bright merry sound that seemed entirely inappropriate.

"Are you talking about my brother's almost psychotic repression or Dean's?" he snarked and Sam couldn't help but smile.

"Yeah, OK. That's fair. Honestly, you should try living with it, the constant longing looks and moments of unbearable sexual tension," Sam admitted. Gabriel waggled his eyebrows. "But I think this is about something else. Cas said something to me, a few months back. It was just in passing and dammit, I didn't think anything of it at the time, because you know. I was focused on the ungodly mess we'd made by setting Amara free." Gabriel's attention was completely riveted on him now and Sam tried not to notice how good it felt. "I was moping I guess, because I'd just gambled the world to save Dean and fuck, I'd do it again in a heartbeat. Even knowing what I know now. Which makes me a bad person, I suppose. And Cas was telling me he felt the same, which wasn't exactly a shock. And then he said, 'I'm not much use to anyone anymore, but if I can make this right, I will.' I heard him, and I was too wrapped up in my own misery to see how defeated that sounds."

"Fuck," Gabriel said with feeling. He leaned over and punched Dean in the arm, hard. Dean twitched and groaned.

"Quit it, Sammy," he muttered. Gabriel rolled his eyes, clearly exasperated.

"I should let you both rot," the archangel said grumpily. "If you hadn't just managed to doom the world two separate ways from Sunday, I probably would. But no, Winchester drama has to come with a side order of Apocalypse!"

"I said I was sorry," Sam said sullenly. "What else do you want me to say?" Gabriel rotated his shoulders and cracked his knuckles.

"Fine. I'll be in touch." Gabriel said shortly, snapped his fingers and was gone. Sam stared at the space where the archangel had been and swore.

"Forget him, Sam," Dean insisted. "I got it wrong. I thought you and he… Well, never mind what I thought. The asshole's ditched us to clean up our own mess and maybe we deserve that but Cas got his ass out of Purgatory and he owes him, dammit. But I am not going cap in hand to beg to that motherfucker, and neither are you." Sam looked away, staring out over the water of the lake. Two small boys were playing with a ball near the water's edge, and their mother hovered protectively on the beach. He gave a sigh, hating how sad it sounded and the tension that dragged at his brother's mouth.

"Yeah. You're right, I know. I'm being stupid. We keep going, just like we always have. We figure this out, stop Amara, get Cas back. We can do this. We don't need Ga- anyone's help." Dean gave him a wary glance at his stumble but mercifully kept his mouth shut.

"OK, then. Are you ready to head home?" Dean asked and Sam shook his head. The ball had bounced out of the younger boy's hands and landed in the water that lapped at the shore. The boy tried to grab it but the movement of the water just kept it out of reach. The older boy began to scold, but did nothing to help. He stood there, hands on his hips and taunted his brother. Sam looked at Dean and felt a wave of gratitude. His brother had his back. He'd always had his back, even when Sam hadn't had his. Guilt was an old friend, a heavy lump in his throat that never went away. He turned his head away, not wanting the tears that threatened at the back of his eyes. Dean either didn't notice, or pretended he didn't. He patted Sam's arm and stood.

"Come on," he said. "Let's go home."

The Bunker, once a place of refuge, felt violated. Even though it was the same, the knowledge that Lucifer had been able to come and go freely here left a sour taste in Dean's mouth. Not to mention… He quickly squashed that thought down, if he let himself even think about what had happened, he might just eat a bullet right now and he couldn't afford to do that. He watched his brother as he pottered around the kitchen, making some God-awful rabbit food that he'd eat because it made Sam happy and these days, precious little did. That Gabriel had taken one look at the Hellish shitscape of their lives and bailed shouldn't have been a surprise. But the full power and terror of the archangel in that motel room had made Dean suspect that Gabriel might not love Sam, might not even be capable of loving anyone but himself, but he was possessive and not willing to share. Dean had hoped that might be enough, but that was apparently the triumph of hope over experience, or some other bullshit flowery phrase that might come out of Sam's mouth.

Cas. Fucking Hell, man. What did I do to make you do this to yourself?

I'm sorry, Dean. But it was the only way. The sense of the angel was warm and comforting in his mind.

Cas! Can Lucifer hear us like this? Dean felt his heart begin to race and his breathing become a little fast.

No. I don't think so. But don't say anything you don't want him to know anyway, just in case. Cas replied.

OK. OK, I can manage that. An image of himself kissing Cas, fuck no, kissing Lucifer pretending to be Cas, flashed through his mind and he ruthlessly suppressed it, but not before he felt a stab of pain from the angel. I'm sorry, Cas. I never meant to make you feel useless or unwanted. There was silence and Dean wasn't sure if the connection between them had been lost or if Cas was just too unhappy with him to talk.

No, Dean. I'm just… I only wanted to do the right thing. Lucifer said he could beat Amara, and I believe him. What other point is there to my existence, if not to do this? Dean's throat began to close. I needed to feel useful to you again.

Cas, what makes you think you weren't useful? Or that I only want you around because you are useful, and once you're not I'd ditch you?

Well, the angel's mental voice was hesitant. I was going on past experience. It was like a knife in his gut. When Gadreel had been possessing Sam, and Cas had become mortal, he'd kicked him out of the Bunker so fast his head must have spun. Because Gadreel had threatened Sam's life if he hadn't.

Cas, that wasn't because of you. That was Gadreel, and he held Sam's life in his hands. I had to choose, and I thought you were the stronger one. Anguish squeezed at his heart, had Cas really thought he'd kicked him out because he was no longer useful? Hadn't he explained all of this already?

Stronger? The angel sounded amazed. You think I'm stronger than Sam?

Hell, yes. I love Sam, and I'll do anything to protect him. But I'm not blind to his weaknesses, Dean admitted sadly.

Dean, I… I lo-

The connection went dead. Just like that. Dean was left feeling cold from the sudden absence of the angel's presence.

Cas? Cas!

Nothing. Cas was gone.

Sam looked over to Dean, who was half-slumped over a book. Not a typical sight, he thought. Maybe he should take a picture? And send it to whom? It's not like you've got any friends. He took a deep breath.

"Hey," he said casually. Dean's head came up like a terrier. "I might have something."

"What is it?" Dean asked breathlessly. "Something to help Cas? Or defeat Amara?" Sam shook his head.

"No. I wish it were. But it might be a case." Dean's shoulders slumped.

"Pass." Sam narrowed his eyes.

"Don't you even want to hear about it?"

"Nope. Focus, Sam. We have two really big problems to solve and no leads. Concentrate on that."

"Come on, Dean. I'm going blind here. I need to get out of the Bunker for a few days, clear my head. So do you," Sam insisted and was treated to a theatrical sigh from his brother.

"All right, all right. Tell me what you've found and I'll think about it."

"OK, so get this. Belinda Mullins, in Greenville, South Carolina went missing three weeks ago. She left work at the usual time, never came home. Her husband called the police, explaining that she had really bad asthma and he was worried. Police put out a BOLO, there's an appeal on the local news, you get the idea. So far, so tragic but not necessarily anything supernatural. She turned up again yesterday. Just walked in the house as if she'd never been away. She has no memory of being missing, in fact as far as she is concerned no time has passed."

"Weird," Dean commented. "But you know, maybe she just had a breakdown."

"Well, maybe. But where was she for three weeks? Her car had half a tank of gas, which is about what the husband said she would have left unless she filled up. Her last service was just four days before she disappeared, so they know what the mileage was. She'd only added a couple hundred miles since then,which given she does a twenty-five mile commute doesn't seem excessive. She seems to have suffered no ill effects, the doctors who examined her said there were no signs she was malnourished or -" Sam wrinkled his nose. "OK, this is a little gross. But analysis of her stool was consistent with the last thing she remembered eating, a tuna salad wrap, some salted popcorn and a handful of almonds that she had for lunch."

"Nice," Dean said. "OK, so are you saying that she jumped forward in time somehow? Like, I dunno, a wormhole or something."

"Maybe," Sam agreed. "I mean, there's plenty of lore on this stuff. And then there's things like the Philadelphia Experiment."

"Dude, that was a movie." Dean said laughingly.

"Well, yeah. But it was based on a true story." Sam insisted. Dean rolled his eyes. "Look, it doesn't matter. What matters is, where was Belinda Mullins for three weeks and why doesn't she remember anything about it?"

"What about her cell?" Dean asked. Sam flicked through his notes.

"Nothing much. No calls after calling her husband the day she disappeared. Time and date were correct, but since most phones get that from the network, I don't know that it tells us anything. Cellphone data from local towers don't register a ping from her phone the whole time she was gone."

"Was it charged?"

"Uh, yeah. She had an in-car charger, so again, nothing to help us out."

"It could be something, I guess," Dean said dubiously.

"I mean it could be an Agatha Christie," Sam admitted. Dean looked puzzled. "British crime writer, wrote those cozy mysteries in quaint English villages. Miss Marple. And Inspector Poirot, the Belgian detective."

"What? Yeah, no I know who she is. Mom used to read her books sometimes." Dean's eyes went distant for a moment. "How is this relevant to our missing woman?"

"Oh! See, Agatha Christie went missing, back in the 1920's.. She was gone for a couple of weeks I think. Nobody knew where she went. Eventually she turned up at some fancy hotel in the North of England, under a false name. She would never explain why she disappeared or what she had been doing, but her husband was having an affair and had asked for a divorce," Sam explained. "So, maybe Mrs Mullins did something like that. But why claim not to remember where she'd been? What did she live on? There was no record of her withdrawing significant cash before she vanished and her credit and debit cards weren't used. Plus, to meticulously ensure that her stomach contents would match her last known meal - that's a whole new level of crazy." Dean nodded thoughtfully.

"It is odd, Sam. No question. I just don't know if I want to go chasing after this right now." Sam looked disappointed so he added, "Look, why don't you go take a look. I'll stay here and keep working. If it turns out to be something, give me a call and I'll come meet you." Sam thought about it for a moment.

"OK. You're probably right, it is a little thin." Sam stood up. "I'll go check it out and if there's anything there, I'll let you know."

The Mullins house was small and a little shabby and the two cars parked on the driveway were more than ten years old. But the yard was neat and the cat that lounged on the front step looked well fed. Not wealthy, but not really poor either. Sam looked at his notes again. Mrs Mullins was a public defender, her husband was a construction worker. He wondered vaguely how well public defending paid. He pressed the doorbell and could hear it inside the house. A dog barked off in the distance, but there was no sign of anyone moving inside.

Sam looked to see if any of the neighbors was watching and then tried the door. Locked, of course. He slipped his lock-picking tools out of his pocket and poked at the cheap lock for a moment and made a satisfied sound as it clicked. He turned the knob quietly and slipped inside the house.

It was the smell that hit him first, like old copper pennies and rotting meat. There was something dead in here and Sam had a sick feeling it was human. Flies buzzed lazily in the hallway and Sam crept across the laminate floor as silently as he could manage and poked his head inside the living room, his gun held out in front of him. There was someone sitting in an armchair, facing the TV, but whoever they were had quite literally lost their head. Sam gave the corpse a cursory glance, a stocky male body that was most likely Arthur Mullins. A creak from upstairs made him freeze and then he moved quickly back out into the hall and up the stairs.

The first two bedrooms were empty, but the third contained Belinda Mullins, mostly naked and covered in blood. She grinned crazily at Sam.

"Well, if it isn't Sam Winchester!" she exclaimed. Sam was getting a little tired of being recognized by monsters all the time. "Where's your brother?"

"Not here," Sam told her. "How do you…"

"Amara has a message for him," Belinda said, nodding to herself. "A message, a message."

"OK," Sam said slowly. "If you tell me what it is I can pass it on." Belinda's eyes went distant for a moment.

"I'm really supposed to tell Dean," she said finally. "Tell him to come upstairs."

"I wasn't kidding," Sam said. "Dean's not here. I came on my own."

"Really?" she said in a soft, childlike voice. "Oh dear." Her eyes unfocused again for a moment. "Amara is most displeased. I've failed her."

"Look, why don't I call Dean now, on my cell. And you can tell him the message that way." Sam suggested, tugging his phone out of his pocket. Belinda rocked back and forth, humming and whispering nonsensically for several seconds. Just when Sam was beginning to think he'd get nothing more out of her, she stopped and nodded.

"Phone him. That will work." Sam punched up Dean's cell and put it on speaker. Two rings and then Dean's gruff voice answered.

"Sammy? You OK?"

"Yeah, Dean. I'm fine. I've got Belinda Mullins here."

"Who?"

"The missing time woman."

"Oh, yeah. OK? Why are you calling me?" Dean sounded like he'd been drinking again. It was only 3 o'clock. Sam sighed.

"She says she has a message for you, from Amara." There was a rustling sound and the clink of a glass hitting a hard surface.

"Really? OK, shoot."

"Hi Dean," Belinda said coyly as Sam held the phone out to her. "Amara says hi."

"That had better not be the whole message," Dean said warningly. Belinda laughed.

"No silly. Of course not. She says she needs you to do something for her. Something important." Belinda laughed again and Sam's stomach roiled uncomfortably.

"And why should I be doing favors for Amara," Dean growled.

"Well, it's not so much a favor," Belinda said in a sing-song tone. "More an exchange. She has something you want. And you have something she needs."

"I'm listening," Dean said shortly. Sam opened his mouth to object but then changed his mind. Dean was handling this OK for now.

"You've got the keys to Lucifer's Cage," Belinda said. "Amara wants them."

"Wait," Dean stuttered in surprise. "How the Hell does she know that?"

"Is omniscient too difficult a word for you?" Belinda snapped viciously and Sam recoiled at her sudden change of mood. "She knows. That's all you need to know."

"Well, then her information's wrong. Or at least, out of date." Dean told her. "We only have three of the four horsemen's rings. Death took his back."

"Death's dead! Didn't you retrieve it then?" Belinda cried. Sam shook his head. They'd been distracted by the spell that had removed the Mark of Cain from Dean and the subsequent release of the Darkness. What had happened to Death, his possessions or even his body Sam had no idea. "We had other concerns," he told Belinda.

"Nevertheless, Amara wants the other three."

"Yeah. And what does she have that we want so badly?"

"A way to rescue your pet angel of course. To push Lucifer out of his vessel." Dammit, Amara certainly understood Dean well enough to know which buttons to push.

"Fine," Dean said abruptly. "Three horsemen's rings for the knowledge of how to save Cas. I'll take that deal."

"Wait," Sam objected. "Aren't you going to ask what Amara plans to do with those rings?" Belinda was laughing again.

"Haven't you figured it out?" she chortled. "She wants to free Michael from the Cage. Raphael and Gabriel are dead and beyond her vengeance. But Michael is still alive." Sam frowned at her. He'd never been a fan of Michael and considered the archangel's absence as no big loss. He felt a pang of guilt, Michael was still inside his half-brother too. But if Amara sprung him from the Cage, what would that mean? Lucifer claimed Michael had lost his mind, but Sam was hardly going to take his word for it. And if by some chance they did manage to kill or recapture the Darkness, would Lucifer and Michael kick off the Apocalypse again?

'Yeah, I figured," Dean said and Sam stared at his phone. He'd forgotten his brother was still there at the other end of the line.

"Then Amara will make the arrangements for the exchange. She will send a message with the meeting place soon." Belinda declared.

"Awesome," Dean said and hung up. Belinda eyed Sam hungrily and he shifted in discomfort.

"So, Sam…" she drawled, "I hadn't appreciated what a delicious morsel you are. Amara only has eyes for Dean it seems. But you're much more to my taste." Sam backed away but he was too slow, she launched herself at him and bit savagely at his neck. He shoved her hard, and she flew backwards against the wall. Her head hit the dresser with a loud crack and she slumped to the floor and lay still. After a moment Sam dragged himself towards her and checked her pulse. She was dead. He sighed and shuffled off to the bathroom to examine his neck, but luckily she hadn't managed to break the skin. He'd have an impressive bruise that Dean would no doubt find highly amusing, but nothing more than that.