A/N: I know it's been a while. A very long while. And I know this is a short chapter, but I'm trying to get back into writing again, so please bear with me! I really appreciate your patience and support.

Chapter Eleven – Leviathan

The air grew colder the deeper Sam went. He could feel the chill seeping into his still-damp clothes, turning the fabric into what felt like ice, and he shivered. The one plus side to the bitter cold was that at least it kept him awake. He was exhausted, but the feel of his own chilled blood clinging to his skin kept him alert, preventing his mind from switching off. At least this way he was making progress.

Clang. Clang. Clang.

The sound of his footsteps were a jarring, ominous counterpoint to his heartbeat, which still raced manically no matter how hard he tried to keep it under control. He was attempting to tread lightly, but the hollow ring of each metal step still felt disturbingly loud as he descended further into the dark. The flashlight did little to help him see more than a few steps ahead. In the distance below, the sound of running water grew closer.

He was just beginning to wonder how far down the steps could possibly go when the flashlight beam finally fell on flat, grey floor and he felt a change in the textures beneath his feet. The thin metal of the stairs gave way to something sturdier; concrete or stone, he suspected, and Sam felt the knot in his stomach untwist just slightly as he spied what looked like light up ahead. Just from the whitish-grey glow and the absence of the menacing red of the emergency lights, it couldn't have been artificial. He didn't know how far underground he must be by this point for natural light to somehow penetrate this far, but then, he wasn't sure how well he could apply the concept of "underground" to wherever the hell he was.

Sam continued onward. His path brought him to a platform at the top of what looked like a vast underground sewer system, judging from the many canals of running water below him and – unfortunately – the smell. Sam grimaced, but continued to look around him. The pale light filtered in from narrow grills in the ceiling above, much too high to reach, and with no chance of discerning what was beyond. Lower down, judging from the high arches of the waterways and the grimy, cracked ceramic tiles, Sam would have guessed that the sewer system was Victorian. Not that that made sense, but his confusion had long since given way to acceptance that he wasn't in a world that made sense anymore.

He was just contemplating why he was supposed to go this way to get the power back on and what he was meant to do now when he heard a voice pipe up again, "The generator's this way."

Sam turned his head to see Lucifer stood waiting for him at the far side of a metal bridge spanning one of the waterways. He shot the fallen angel a customary glare, although that had been a surprisingly helpful remark. "The generator's in the sewer?" Sam's tone was only half sarcastic.

"The generator's in the basement. You get to the basement through the sewer."

"Just great," Sam remarked, taking the first step to continue across the bridge. "You decided to start being helpful all of a…" The final part of that sentence was abruptly cut off as a roaring noise sounded from somewhere below him.

The metal frame of the bridge shook and rattled, and Sam half-scrambled, half-fell backwards onto the studier platform behind him. From below the bridge, a shape was emerging. It was wormlike, gigantic, almost seeming too swollen to fit inside the narrow waterway that held it. Its skin was black and glossy like oil, and it moved with an almost viscous quality as if it were made of tar. Sam imagined that if he were to touch it, his hand would come away stained with black stickiness.

The roaring finally gave way to the splashing of water as the head of the thing emerged above the parapet, and Sam felt a chill run through him. It had no eyes, nor nose, nor any facial features he could discern save for the rows and rows of teeth that lined the gaping chasm of its mouth. Fear swept over Sam in a wave. A forked tongue flickered out from the depths of the hole between the monster's jaws, and Sam wondered if it was going to lunge for him, but then – mercifully - the entire creature began to descend again. Its squelching mass crawled back into the space from which it had emerged, slithering away with a wet slurping noise as its skin clung to the sewer walls.

Sam shivered. The worm had vanished as suddenly as it had appeared, but his relief did nothing to stop the revulsion that ran through his body. If that thing was out there, he was going to have to be careful. Doubly so than before.

Shakily, the hunter picked himself up and shot a glance at the hallucination of Lucifer, standing nonchalant as ever as the far side of the bridge. He swallowed nervously. "What was that?"

Lucifer shrugged. "Leviathan, Sam. In its true form. You knew they were sea serpents, right? Originally, before my father locked them away."

"Wait, what?" Sam's already exhausted brain struggled to process that, trying desperately to make sense of things. "You're saying the Leviathan have something to do with all this? They're why I'm here?"

"What do you think, Sam?"

There was a pause, in which Lucifer surveyed Sam calmly and Sam's mind tripped over itself to come up with an explanation. After a beat, he shook his head. "No. I still think this is you. You're fucking with me."

Once again, the fallen angel did nothing but shrug. "Maybe. But I'm still the one you're going to have to listen to if you want to get out of here. Now, do you want to get the power back on and go save your brother or not?"

Sam was about to reluctantly agree when he suddenly froze. Another chill ran down his spine. "So…you admit Dean's in trouble? You said you didn't know what happened to him."

Momentarily, a flicker of annoyance passed over the angel's face, looking as if he'd been caught out. "Well, Sammy, you certainly seem to think so, and I am your subconscious after all."

"Tell me what happened to him, Lucifer." If the command had been directed towards a human being, the anger in Sam's tone would have cowed anyone.

"You're going to have to figure that one out for yourself." Lucifer's words almost seemed like a taunt.

Sam just glared harder for a few moments, breathing heavily, wondering if he should just finally have his outburst and let all the fear and anger and frustration out and scream until the angel told him what had happened to Dean. But when he wasn't sure if he would just be arguing with a figment of his own imagination, he tried to keep his mind in check. "Alright," he snarled after a beat, "I will. And if you aren't going to help me, you can fuck off."

Lucifer looked affronted. "And after everything I did to get you this far. But fine, have it your way." A moment later, he was gone.

Only then did Sam take a deep breath and finally began to stride forward across the bridge, his step even more purposeful and determined than before.