Inspired by the lyrics of the song 'Sleeping sun' from Nightwish. I used the lyrics in the fic, towards the end. Enjoy. :)

"I wanna say yes."

Sam tried to appear brave and courageous; to assure Dean there was at least a tiny chance that he could beat Lucifer and to show the devil that he wouldn't go down easily. But he was frightened. The demon blood he had drunk didn't stop him from feeling frightened. Usually it filled him with confidence and strength but not this time. Or maybe his fear of Lucifer was greater.

"Excuse me?"

Lucifer looked at Sam intently, his pure ardent eyes in stark contrast with the broken skin of his vessel's face. Sam felt like the world shrank into the small room, or more precisely between him and Lucifer. He knew Dean was by his side but he could not acknowledge him, Dean was so painfully unimportant in that instant. And of course there were the two demons – and then they were not.

"You heard me. Yes."

Sam stared defiantly at Lucifer. They stood very close and Sam could feel the coldness that radiated from the latter. It felt strangely familiar, comforting and reassuring. Sam didn't know if Lucifer played some tricks on him but he had to hold on the fact that he wasn't coming home after never having been there. Because it felt like that; Lucifer's proximity intoxicated him and urged him to come closer, as close as possible to Lucifer's embrace.

"I know you have the rings, Sam."

Sam wished he could say he was shocked. But he wasn't at all, he thought he could sense some of Lucifer's emotions; very roughly but still. He didn't doubt that Lucifer as an archangel was able to guess more from Sam's thoughts. Their eyes met for a little moment, mere glimpse and they knew what this situation was leading to.

"So he knows. Doesn't change anything."

Sam uttered to Dean to tell him he was sorry for what he was going to do. His eyes were fixed on Lucifer, even as he talked to his big brother, he held the angel's gaze. Dean needed his words but he was unable to tear his sight from who was soon to invade his body.

"Yes."

With one last glance at Dean, Sam braced himself. He had no idea what to expect; would it hurt? Would it feel so amazing he would be paralysed by joy? Would he forget everything? Fear overtook him for a moment but then he caught a glimpse of Lucifer's face. He saw pure delight there; not triumphant delight, just sheer happiness and felicity. Soon enough his thoughts started to melt as the purest, brightest light that ever existed filled the room and rushed all too happily towards Sam. Dean had shielded his eyes but Sam stared in awe and astonishment as Lucifer's essence crept into every single fibre of his being.

John smiles at his children as they sit side by side eating ice cream he had bought them. Sam with the sweet all over his mouth, Dean keeping an eye on him for the whole time should something-

Michael takes Lucifer into his embrace and clings onto his younger companion as they laugh at Raphael who tries to free himself from a trap the two set for him. Lucifer looks up to his brother-

Sam throws a backpack on his right shoulder furiously and turns towards the door. John shouts at him. Dean cries and begs him to stay. Sam turns away from his brother, tears in eyes and he stamps towards the door without looking back. His chest tightens-

Lucifer stands proudly facing his Father but he feels frightened and sad. Michael watches him from God's side and his posture and expression reveals no emotion but devotion to Father. Lucifer repeats his words, repeats them over and over. Michael diverts his gaze-

Dean gives Sam a crooked smile that hides worry. Sam doesn't know how he earned the chance to see his brother again but he can't hide how happy he is. After thinking he would never see his brother again, or at least in a near future, Dean is there asking Sam for help-

Michael doesn't even look at Lucifer as he opens the cage designed for the younger archangel. Lucifer tries to get his brother to look at him, to see him behind the task he represents but Michael would not hear about it. He raises his sword-

Sam?

Lucifer?

For a little moment neither of them had control over their shared body. They tried to stretch themselves into the remotest parts of it but it was difficult. Where Sam tried to reach, there was Lucifer and so instead of fighting for control, they were merging together and claiming the body together. Sam was self-conscious upon seeing how vast and bright Lucifer was compared to himself but the latter would not hear about it. He insisted Sam was just as beautiful as him or even more.

I never knew if it would work.

What?

Keeping you.

Lucifer gripped Sam tighter as if in fear they might be separated as a result of his words. Sam didn't even pretend to pull away, he accepted his place gladly. And that place was curled in Lucifer's embrace, surrounded by the angel, safe and sound.

Why are you not fighting me?

Why aren't you?

They were still, not ready to face the world just yet. Sam felt content like he had never felt before.

Could I?

If you wanted? Yes. You are strong Sam, you were made for me; fierce, powerful. But you don't want to, do you?

No. Should I feel bad?

You should do what you feel like doing.

I feel like taking a nap. Will you not destroy the whole world when I'm away?

I shall try.

Sam fell into a state similar to unconsciousness. He could see what Lucifer was doing, but he was too happy in his warm, dark spot within their shared body to try to interfere. Besides, Lucifer really didn't do anything that would make Sam feel he had to react. Enveloped in thousands of layers of Lucifer's grace he tried to find a reason why he should feel bad for not fighting as he promised Dean.

He'd said he would try to get Lucifer into the cage and he'd been ready to give his life in order to execute his task. But now... Lucifer was so thrilled to be walking the Earth. In the thoughts that sometimes escaped Lucifer's awareness, Sam could see he found pleasure and amusement in ordinary things and to Sam he seemed like an overgrown baby that is exploring the world for the first time. Suddenly the motivation for fighting Lucifer was petty. He didn't know if it was Lucifer's tactics but he cared little when he saw Lucifer let Dean go.

I have no interest in killing him and if you want to keep him, your wish is my command.

Lucifer whispered to Sam reassuringly. Sam just stirred a little, murmured and pretended he wasn't there, asleep and deaf to everything but Lucifer. He curled into a ball and gave in far sooner than Lucifer had thought and the idea was both flattering and unnerving.

The sun is sleeping quietly,

Once upon a century.

During the first few hours, Lucifer often caught himself stopping in what he was doing just to check Sam was still there. From time to time it felt like he was alone – alone once again – and it terrified him. He had to take a break and hold Sam in an embrace, to feel his substance even if the human was fast asleep, enjoying his deserved peace.

Wistful oceans calm and red,

Ardent caresses laid to rest.

In these situations, Sam stirred and responded in confusion. He feared something happened because Lucifer would not wake him up without reason. When he was assured that Lucifer just wanted to marvel at the fact that they were together, he calmed down again, soothed by Lucifer's sweet words of love and compassion.

For my dreams I hold my life,

For wishes I behold my nights.

There were moments when Lucifer wasn't sure he'd be able to go on without Sam. Earth was so confusing, humans were so loud, strange and diverse; Lucifer was used to simplicity – there was a strict hierarchy in Heaven, nobody dared to question anything and his cage was all too monotonous. But there was nothing more important than Sam and Sam wasn't ready to face the world by his side just yet. And it was fine because after all, Lucifer was doing it for one thing only – his future with Sam.

The truth, at the end of time,

Losing faith makes a crime.

Sam did wake up eventually. It came seemingly out of nowhere – there was no external sign of him reacting to something but suddenly, Sam was awake and claiming his right over the body. Or rather, after having remembered what he was supposed to do, Sam decided he couldn't possibly disappoint Dean by admitting to being happy just this once. Because he was happy with Lucifer. Even without any interaction between them, there was never silence; their souls communicated on their own, overjoyed to finally be reunited. And Lucifer never ceased believing Sam would let go of his previous life. It only required time and Lucifer had plenty of it.

I wish for this night-time

to last for a life-time,

The darkness around me,

Shores of a solar sea.

Sam was struggling. He knew he should be fighting Lucifer and he knew he didn't want to. He could say he was in shock after they merged so his affection for the Devil was justifiable, but what now? He could no longer pretend it wasn't him who wanted to give everything and even more to his other half. He wished he could know that no one would ever find out he was still alive. That way, he could be with Lucifer and nobody would blame him or want to get him back. But on the other hand, he wanted to show Lucifer off. He wanted everyone to know that the archangel chose him, was his and loved him. He wanted to prove he could be loved to all the people who have ears to hear it.

Oh, how I wish to go down with the sun.

Lucifer was patient. He'd spent centuries despairing, suffering in Hell without a single conscious thought or wish. He'd overcome the worst pain only to be reminded of the terrible loneliness he felt, only to remember he would spend eternity in solitude; in the fiery pit where all his fears incarnated to torture him, he would languish until the end of the world or even longer. But at some point he remembered another thing – a promise. Somehow, he would meet his soul mate, he would meet the perfect being created solely for him but he was not to know what form this being should have. It was the last cruel joke played on him when this being proved to be a human – the race he promised to despise. And yet, he knew he would use this lesson – not be taught anything, that was for sure. Soon enough though, he understood that it would not be that easy; the power that drew him towards Sam was so intense it was hard to keep himself together.

Sleeping,

Sam argued a lot with Lucifer and even though their disputes troubled the angel and he wanted nothing more than for Sam to understand his views, he enjoyed their conversations. He loved how their shared face changed when he talked and when Sam interrupted him. They had their ways of expressing themselves and it could be seen in their eyes, heard in their voices and felt in their heart. Then, when Sam was mad at him and wanted to tease him, he turned into himself and didn't speak to Lucifer for long minutes or even hours. In that moment, Lucifer wished they could be not just one body but one mind as well so that he could invade Sam's thoughts.

Weeping,

Lucifer kept following his plan. Sam didn't like it but he never said anything against Lucifer. Instead, he resorted to his silent defiance and pretended to be busy with his own thoughts while he in fact did nothing else but mourn over his lack of courage to stand up to Lucifer and tell him to stop.

With you.

Lucifer explained what he was doing, commented on their surroundings, where they were going and why even when it seemed that Sam wasn't paying attention at all. If it was because Lucifer liked to talk, because he didn't care that Sam wasn't listening, if he hoped that he'd catch Sam's attention or simply because he didn't believe the human didn't hear his words, he was not sure. But Sam understood what he was being told and that was what mattered. They were together. Even if their relationship was not ideal, it was a relationship and that counted.

Sorrow has a human heart,

From my God it will depart.

They were standing in the Stull cemetery. Sam didn't remember the place, he couldn't have, he didn't go there as a child like Dean did. The air was crisp and Sam thought that if there was a perfect weather for cemeteries, this would be it. Tufts of fog hovered just above the ground, creating a smoky atmosphere like in a theatre when it is artificially created to add more severity to the situation. Some of the headstones were broken, some were covered in moss or lichen, some were smoothened by wind, rain and chemicals and others had perished for good so that Sam could only presume their existence. And this was the place Lucifer chose to meet his brother. This was the place where he intended to ask Michael to stand down and never start the fight that would destroy so many of the precious humans Michael was supposed to protect. This was the time and place Lucifer had chosen for this occasion and Sam thought it was a bad idea. But Lucifer was not able to think properly; he was nervous, anxious even when he imagined meeting his brother. Sam could feel his distress, his fear and his doubts. The angel wished to get everything right with Michael, but deep down he knew it wouldn't work and it filled Sam with remorse and compassion.

A moment for the poet's play,

Until there's nothing left to say.

Despite Sam's mistrust towards Michael, it still shocked him what the oldest archangel said. Sharing a body with Lucifer, it was difficult for Sam to stay neutral, but he was pretty sure Michael was a dick for acting like this. Lucifer offered to stand down, to stop hating humans, to walk off the chessboard peacefully. All Michael gave back was reminder of a distant father, duties and roles. He didn't even try to pretend to think about Lucifer's words; he turned his back on his brother which shocked Sam and hurt Lucifer. With agonizing pain in their chest, Sam and Lucifer looked away.

I wish for this night-time

To last for a life-time,

Dean came in time to save the day. Castiel was too stupid to stand back when Dean was involved. Sam was too perplexed to do anything when Lucifer's frustration burst out and clouded the angel's mind. Sam didn't even realise his hands were crushing his brother's face. All he could think about was Michael's harsh words; the way he gave up on his brother – his little brother who after all that time loved him and looked up to him. Sam could feel Lucifer's despair; he didn't wish to go against Sam's wishes and he felt repulsed by the image of fighting Michael. And while Sam was thinking about this, Lucifer beat up Dean, taking out his rage on another big brother. All he knew was that Dean came to separate him and Sam and he would not let him. He could not let him. Sam was all that was left to Lucifer and he wasn't going to let go.

The darkness around me,

Shores of the solar sea.

Lucifer knew he couldn't be helped. What was he? A misplaced failure, renounced by his family, despised and feared, unable to give love. He was the devil, wasn't he? He was beating up the person who mattered the most to his soul mate and he couldn't stop, wouldn't stop because he was so twisted and broken. Sam was there, too astonished to do anything but Lucifer could feel his reassuring presence, the tremendous warmth of the pure soul and the bright blare it radiated.

Oh, how I wish to go down with the sun,

Suddenly Lucifer felt like he would give up everything only to become even with Sam. He wished he was mortal so that his torment would end with his death. He wished he could be knocked unconscious to take at least a little break. For once, he wanted to be the mere human he so despised.

Sleeping,

Sam caught a picture his and Lucifer's mind was processing and he shouted internally. There was the plastic soldier stuck in the Impala; a life-less, meaningless piece of ugly green plastic that carried so many memories. Sam screamed and Lucifer froze with his fist right above Dean's face, ready for another blow. Sam begged, cried and fought and Lucifer gave way to him. He was devastated but Sam was everything, Sam was the only thing that mattered and Sam had to be happy.

Weeping,

While Sam pretended he was controlling Lucifer and Dean kept watching him, Lucifer curled up into a tight bundle and shook. All his life he had craved one thing – not only one, for sure, but he had wanted one ever since he was created – Michael's love and approval. And that was gone. No way would he ever be with his brother again and it felt almost as bad as being separated from Sam.

With you.

Lucifer stared at Michael who reappeared by his side with horror; what was he supposed to do? He didn't know, he couldn't know, he was so hopeless-

But Sam did know. Sam embraced Lucifer carefully and for a while there was nothing but their souls, touching each other, vast, bright and beautiful. For a moment, it was just them, Lucifer and Sam Winchester, an angel and a human, the Devil and his vessel, his lover, his friend, his soul mate. For a moment there was nothing else.

Sleeping,

Sam pulled away and without deciding to do so, they reached for Michael and grabbed the archangel. After that, there was just the all-too-familiar heat of the Cage and a long, terrifying fall. Sam screamed in Lucifer's arms, Lucifer was trying to envelope his whole being around the human. They lost the body as they fell but it wasn't important because why would it be? It was of no use to them in Hell where everything lost meaning apart from pain and suffering.

Weeping,

Finally, they hit the bottom of the pit. The cage rushed to get them, all too happy to have something to do again, somebody to torture. Lucifer didn't let go of Sam even when he started crying and shaking under the influence of the Cage. Lucifer couldn't see Sam's torment and vice versa, but they clung onto each other as they suffered in the dark.

With you.

Sam did know one thing; whatever was going on, whatever they would go through, they would be together. He would never leave Lucifer, he would never let go of him. If this was their infinity, their endless love, then so be it. It would not be perfect but Sam never expected perfect for himself. And if it included cuddling with the Devil in the depths of Hell, he was not going to complain. As long as they were together, he could cope.

With you,

With you,

With you...