Rimmo nín Bruinen dan in Ulaer!
(Rush, waters of Bruinen, against the Ringwraiths!)

Summary: The Valar are worried. Sauron is gathering his strength, the Ring has awoken from its long slumber in the Shire, and its current Ringbearer has just been fatally stabbed upon the Weathertop. The heir of Isildur does not have the strength to carry Frodo further, and even as the Valar watch from their Halls in Valmar, things seem dire for Arwen Undómiel as the Ringwraiths close in around her. Desperate and out of time, the Valar do something unheard of in all of the Ages of the Earth: they reach out to a pantheon not of their own. Reaching through dreams and across rivers, Irmo the Dreamer aids Ulmo the Sea King in contacting a faraway counterpart, whose son has already shaped the course of destiny in his own world once before. Now, he must do the same for Middle-Earth, or all may be lost… (takes place after The Last Olympian but before The Lost Hero)

"Are you certain this is wise, old friend?"

The voice was melodic, ancient knowledge and hidden power clear to all present, as the gathering of powerful beings looked on with rapt attention to the events unfolding a continent away. As well they should, for the fate of all the world may depend on how said events would unfold.

Beings that in another world would have been likened to angels or gods watched as Arwen, daughter of Elrond Half-Elven, narrowly dodged the reaching claw of a Nazgûl, only to almost collide with another specter that had closed in from the opposite side. It was only her millennia of skill in horse-riding and the swiftness of noble Asfaloth that had kept the elven woman a hair's breath ahead of her foul pursuers.

More pressingly, was that it had kept her charge safe as well, if only just.

Frodo, son of Drogo and heir to Bilbo Baggins, perhaps the most famous Hobbit of his Age, was barely clinging on, both to Asfaloth's saddle, and to life itself, the dark wound in his chest flaring in ice-hot agony whenever a screech from the pursuing wraiths pierced the air.

"See for yourself, Oromë. The girl is barely holding on. The Hobbit is almost gone already. They will not make it to Rivendell. We must send aid." A strong voice, usually filled with laughter and mirth now utterly serious, answered the earlier question.

The now named Oromë the Horn-Blower glanced at the speaker from underneath snow-white hair, the burly Tulkas flexing his bulging muscles as he stared down into the pool on which Manwë the Blessed One had projected the flight of Arwen Undómiel. All of the Valar were uncharacteristically restless as they watched each narrow escape the desperate elf made, but Oromë knew that out of every Ainur present, it was Tulkas who wanted above all else to jump to the woman's defense.

As the Champion of the Valar, the golden-haired Ainu felt that the protection of the Free Peoples from Melkor's surviving lieutenant was his responsibility and he would've leapt across the entire breath of the ocean Belegaer, which separates Aman from Middle-Earth, across the Girdle of Arda in a single bound, if he could.

Actually, Oromë conceded to himself that Tulkas probably could preform such a feat, but wouldn't. Not until their Elder King had given him permission to do so. Looking back towards Manwë, to whom he had originally asked his question, the Huntsman continued.

"While I do not agree with your proposal, I do understand. We all wish to come to their aid. Should Arwen fall here, Sauron will no doubt bind all the lands of Middle-Earth in a second darkness. It will not be long after until he sets his sights upon Valinor itself, for evil such as he can never rest as long as a power such as ours exists."

"Pah! I wrestled the Marrer himself, bound him in chains! This Sauron will soon meet such a fate should he set foot upon the shores of Aman!" Tulkas boasted, but it was Nienna who responded in soft, melancholy tones.

"Do not be so certain, brave Tulkas. Much has the Light in Arda faded, while the Darkness has grown ever stronger, hiding in the corners of the world. Gone are the days of old. The tales of heroes as Findelfin, of Eärendil and of Tuor and Túrin have now passed from legend into myth. There is strength and honor still in the lands of Middle-Earth, to be found amongst its noble people. But it is a strength nearly spent. The Elves are leaving its shores, journeying to our Undying Lands. The Dwarves have lost many strongholds and retreat further and further into their darkened Halls. The great Houses of Man have all fallen, the blood of Numenor all but spent. The fate of Middle-Earth, of Arda itself, rests now upon the too-narrow shoulders of a poor Hobbit, nearly gone from this world. A hero is needed, to turn the tide, lest all that we have created, all that we have bled for, will fall to ruin."

"Then send me! If all strength is lost, if no hero can be found, then send me to their aid! Let them rally behind my strength, let them gain courage from my fearlessness! Let me help them!" Tulkas boasted, though his claim turned into a plea as he addressed the still-silent Manwë, only settling down when his wife, Nessa the Dancer, placed a fair hand upon his broad chest.

"Have you forgotten already, brave Tulkas? We have sent them aid. In the fight against the Great Enemy, our struggles sundered so much of Middle-Earth, we vowed that no Valar would mingle in its affairs again, lest the panicked death throes of our foes would bring further ruins to those lands. Instead, we sent our chosen Maia, the Istari, to teach them, to rally them and to watch for the stirrings of evil wherever it could be found. Curumo's betrayal has shocked and saddened us all, but Aewendil's care for the beasts and trees of the lands has done much to halt the spreading sickness of Sauron's will and Alatar and Pallando still make the enemy's hold upon the East untenable, as they have done since the dawning of this Age. And let's not forget Olórin still fights for us and for all of Middle-Earth. The Heren Istarion may yet succeed in their goal, even if one has fallen to temptation." Estë the Gentle replied, still holding onto faith and many of the present Ainur, both Vala and Maia alike, nodded their assent.

But the Hall fell silent when Manwë finally spoke, his voice measured and solemn.

"All of you have raised valid points. The lands of Middle-Earth do not have the strength they did at the dawning of the First Age, lack the heroes of old that struck blows against even the most dreadful of foes. Not even Glorfindel, mighty as he is among the Elves, can hold off all of the Nine on his own, not when Sauron can yet call upon many more enemies still to pursue the Ringbearer. Curumo has betrayed us, but the other Istari still oppose the Darkness and should they manage to rally the Free Peoples, victory may yet be attained, snatched from the jaws of defeat."

Manwë Súlimo fell silent for a moment, before he lifted his sapphire blue eyes from the vision in the pool for the first time since the impromptu meeting had begun.

"The risk is too great. On my order, we Valar abandoned the Elves once before, to fight Morgoth on their own. And while this Sauron may be lesser in evil, so too are the Atani lesser in greatness. I will not be turned from aiding the Free Peoples a second time. A hero must be sent, to aid the race of Man, and all who would oppose evil." The King of Arda proclaimed, his voice strong and steady, even if those that knew him best could still hear the millennia old guilt hidden beneath his words.

"If we are not to interfere, but should send yet another envoy in our stead, then my Halls are filled with those who are worthy of re-embodiment and who would gladly die a second death if it sees Middle-Earth saved. I know that Ecthelion, for one, would be gladdened to see his battle-brother Glorfindel once again." The deep tones of Námo, the Judge of the Dead and Lord of the Halls of Mandos, rang out across the meeting, but to the surprise of all present, Manwë shook his head.

"Your offer is much appreciated, and I would not begrudge any of the valiant heroes in your Halls a second chance at drawing their weapons against the oncoming darkness. But to give them a new body would take too long. Additionally, this is the Age of the Atani. A Man must be sent, one with enough strength in his blood the armies of Mordor may yet break upon his blade."

"No such man exists, my friend, outside of Isildur's heir. Valiantly though he may have fought against the Riders upon Amon Sûl, he cannot aid the Ringbearer now. There is no such strength as you describe in Middle-Earth." Oromë Aldaron once again spoke up, bringing the discussion back to its original point as all Ainur present stared at the contemplative Manwë.

"Indeed. Not in Middle-Earth, no. Which is why we must look beyond."

A rush of hushed whispers rang out throughout the massive hall as gods and angels couldn't contain their shock at the proclamation. Outwardly, Oromë's expression barely even moved, beyond an almost imperceptible tightening around his eyes, but his apprehension was still clearly felt to all as he spoke up again, his tone imploring his King to see reason.

"Again, I ask, do you think this is wise? We have no certainty of what lurks beyond the swirling depths of the Void. The last time something from that accursed realm entered into our world, the Trees were brought to ruin by the foul hunger of the Great Spider Ungoliant. Who knows if more of her terrible kind lurk in its unfathomable depths, or mayhaps even beings older and more cruel still." Oromë pressed, his hunt alongside Tulkas after the fleeing spider and the accursed Melkor still fresh in his mind, even as the memory itself was thousands upon thousands of years old.

For as long as the lifespan of Arda itself, he reckoned those memories would linger with him, the indescribable wrongness of the cloak of Unlight that Ungoliant had weaved to cover her tracks still sending shivers down his spine. It had not merely been darkness, as that was simply an absence of light. The horror that the Great Spider had left in her many-legged wake has seemed actively opposed to light itself, both hating and devouring it, to the point nothing but emptiness and sorrow remained, a nightmare made manifest. So thick were the layers of horror that not even Oromë's skilled eyes or Tulkas' boundless will could aid them in tracking the foul creature.

It was the only hunt he had ever failed, and since that horrible day, when the Two Trees of Valinor died and the Wells of Varda ran dry and the light in Arda would forever more be dimmer than before, Oromë beheld the Void not merely with a sense of unease, but a sense of contempt as well.

He did not trust that any good could come from this plane, to purposefully reach into it and call to something on the other side in the hope that it would come to their aid, instead of adding further death and peril to their diminished world.

"I understand your fears, dear Oromë. They are not unfounded. But, if we do not act, we surely will invite destruction upon the creation of our Father. I cannot abide that. I shall not abide that." Manwë, usually kind and warm, now spoke with certainty and authority and Oromë bowed his head towards the second greatest being in Arda after Eru Illuvatar himself.

"Then what do you propose, my King?" the Huntsman asked instead, surprised when Manwë turned his sapphire eyes towards Irmo and Námo.

"Dreams and waterways may prove to be roads to destinations further than any of us thought possible. Irmo has told me, long ago, that he has felt the stirrings of dreams from far away, beyond any border known in Arda. Powerful dreams, old dreams. Dreams of another pantheon. He should be able to contact one of their number. Given the importance of waters and rivers in our world, Námo should be the one to reach out towards them, to ask them for their aid." Manwë spoke, and Oromë realized the Elder King had thought of this action long before all the Ainur in Valinor had been called to his Hall to view the desperate struggles of Arwen and Frodo.

"They'd better move with haste. The girl cannot hold on much longer." Tulkas' deep voice rumbled, his eyes returned towards the reflective pool, where to the rising fear of many present, the Nazgûl had clearly grouped up on Arwen's location, galloping nine abreast as they ran the Elven princess down across the steppes.

And they were gaining on her.

Surprisingly, a deep chuckle came from the Sea King, whose eyes had looked far ahead, focusing on where Arwen was riding towards, instead of focusing on what she was fleeing from.

"The Bruinen? Good. Very good. This may yet work." Námo said confidently, stepping towards Irmo and holding a mail-clad arm out towards the smaller Vala.

"Come then, Irmo. Lead me, so I may speak with this counterpart of mine you have found and beseech him to send us a champion in our hour of need."

Irmo merely nodded, clasping forearms with Námo as both Valar closed their eyes, deep in thought as their minds travelled far away from them, farther than any being in Middle-Earth had ever traveled, or even thought possible.

As they did so, the rest of the Ainur focused on the reflective pool, many of them subconsciously holding their breath as they wondered why the Sea King had been so pleased with the approaching Bruinen.

In a different world, in a city unlike any ever seen in Middle-Earth called New York, a young man unlike any ever seen in Middle-Earth called Percy Jackson, slept fitfully. Not that this was unusual: as the child of one of the Big Three, Percy had a rather large target on his back (which he felt was rather unfair. It wasn't as if he had asked to be born as one of the most powerful demigods in the last century or so), so sleep didn't come easily to him even on the best of days and when it did, it was usually filled with odd, semi-prophetic dreams that never made any sense to him after he had woken up.

This time was different, however. It was a dream alright, as he had never been in this particular part of the Underworld before. While Hades (the realm, not the god) was usually dark and gloomy (okay, so perhaps it also applied to the god), this particular island made the rest of the Underworld seem like Disneyworld on a sugar high.

The island was large, two to three times larger than the Isle of the Blessed and was sat square in the middle of a river, which instead of the usual blue (or blackish, as the rivers in Hades tend to be) was a milky white. Straight in the center of the island was the entrance to a humongous cave, that seemed unnaturally dark, not because light failed to penetrate it deeply enough, but because it seemed to actively swallow up what little illumination there was to be found this deep in the Underworld.

Strangely enough, there was a veritable field of poppies stretching down towards the banks of the island, their colorful red a stark contrast with the swathe of blacks and greys that colored the rest of the realm of the dead.

But while Percy very clearly found himself in a dream, which wasn't that unusual, the difference was that normally he was the only observer in his own mind (save the odd time Kronos had managed to peep in on Percy's subconscious thoughts).

"Percy?! Oh, thank the Gods, what is going on?! I was just snuggling down with this nymph-"

Turning to his right, Percy smiled at one of his oldest friends, the satyr Grover hurriedly making his way towards him, his goat legs moving erratically as the man tried to not crush (too many) poppies underfoot.

Or underhoof? A question for another day, as Percy turned to his left and felt his heart sink down to somewhere in-between his knees. Not because of who he saw (in fact, he was rather pleased with who he saw), but rather what he saw in their expression.

As Percy had learned from experience, the moment Annabeth starts looking terrified, either begin looking for a spider to squash, or unsheathe your weapon, strap your armor on tighter and pray to whoever your divine parent was to send a little good luck your way because you were gonna need it.

"Annabeth?" he hesitantly ventured, already creeped out by the dark cave in front of him and the weird river to his back, his hand dipping in his pocket, his confidence bolstered by the feeling of his pen in his palm.

While the saying went that the pen was mightier than the sword, Percy privately thought you were still better off if your pen could become your sword if your enemy was illiterate, which just happened to be the case for the majority of the slavering monsters in Tartarus who were on a strict diet of demigod-only meat.

Hearing the tension in Percy's voice and finally seeing Annabeth's stricken expression when he leaned around his friend's broad shoulder, Grover's loud complains immediately petered out as he grabbed his trusty flute closer to his chest.

Hearing her boyfriend call out to her snapped Annabeth out of her stupor, but did little do diminish her fear as she moved over to Percy's side, taking her trusty Yankees baseball cap out her backpocket as her eyes never left the gaping maw of the unnatural cave in front of them.

"Percy! Do you know where we are?!" she hissed underneath her breath, her entire body on high alert, which automatically put Grover and Percy on guard as well (or even further than they already were at least).

"No clue. I don't even know how we got here. I thought I was just having another dream, until I saw you guys." Percy admitted, Annabeth's fearful expression putting him on edge enough that he took Riptide out of his pocket, though he didn't uncap it just yet.

"This is the home of Hypnos! It's his cave, where no light will ever enter, and to our backs is the river Lethe! One drop of that stuff and you'll begin to forget everything about your life, until nothing's left!" Annabeth hissed and with a flash of bronze, Riptide sat comfortably in Percy's hand in its sword form.

The home of a god who had decided to sit out the war with the Titans (and therefore clearly wasn't all that interested in the survival of demigods, or indeed, the world as a whole), along with a river of purified "Nope" at his back? Yeah, it was time for the sword to prove it was just as mighty as the pen.

"The God of Sleep? I mean, that's good, right? Yeah, he didn't do much during the War, or anything really, but since Percy's wish gave his kids their own cabin, everything's good now, right? Maybe we'll get lucky for once and he'll actually like us?" Grover attempted halfheartedly, his flute already at his lips as his tail twitched with nervous energy.

Annabeth merely shook her head, her signature stormy eyes wide open as they remained glued to the wall of darkness that covered the entrance to the cave like a shroud of nothingness.

"You don't get it: Hypnos is a son of Nyx and Erebus, primordials of Night and Darkness. He shares his home with his brother, Thanatos, the embodiment of Death! We definitely should not be here! Anywhere near here!"

"Oh. Oh, that's very bad. Perc, my man, mind yeeting us over the scary river? Now?!" Grover said, his voice climbing a few notes higher as his fear rose further, slowly backing away from the perpetual darkness oozing around the entrance to the cave.

Percy already made to fulfill his friend's request, when a voice resounded from within the unfathomable darkness in front of them. Given the ambiance of their surroundings and the information Annabeth had just told them, Percy half expected the voice to sound unnaturally deep, like two slabs of granite grinding against each other.

Instead, the voice was rather light and youthful, with its only unusual quality being how sleepy it sounded.

"Hey! Hey guys, wait up! Don't go yet, I got something important to tell you! Guys?"

Half-striding, half-stumbling out of the perpetual gloom of his cave came a youthful man (Percy would go as far as to say boy-ish) with hair that was whiter than snow, clad in a cloak that seemed to be made from the night sky itself. As he came into the (relative) light of Hades, he squinted his eyes shut, shielding his face as he let out a monstrous yawn.

His appearance was so sudden and… different from their expectations, the two demigods and one satyr stood rooted from the spot, instead of fleeing in the face of the twin of death.

Finally finishing his yawn, Hypnos blinked a few of times, before weary eyes settled upon his guests.

"Oh, good! You're still here, that's good. Listen, uhh, we got a problem and we need you guys to solve it. Alright?"

"… what."

Not the most elegant answer, Percy could admit that much, but he felt it was appropriate for their situation. Even by demigod standards, hell, even by Percy's standards, this entire interaction was just plain weird and with the immediate threat of horrible death or forgetfulness gone for now (or at least hidden behind a surprisingly nonthreatening façade) Percy found that all he really wanted right now was for him and his friends to just wake up from this shared dream-vision before things went off the rails even further.

Which of course they immediately did.

"It's alright son. While a bit… crudely said, Hypnos is not wrong. We are in need in your aid."

Seeing his father, in his signature Hawaiian shirt and cargo shorts, leisurely step out of the creepiest cave he had ever seen in his entire life (not helped in the least by the knowledge that that was the place where Death itself took off his shoes and kicked up his feet) jarred Percy so much he dropped his guard altogether, staring from his dad to the still yawning Hypnos and back again with a baffled look on his face.

Judging by his bashful grin, Poseidon at least had the good grace to acknowledge just how utterly strange this whole situation was.

"What's going on Dad?" Percy managed, and Poseidon scratched his beard in thought.

He went to speak, but mid-yawn, Hypnos opened one eye, slyly looking in the God of the Seas' direction.

"Careful how much you tell him, Poseidon. This is close to bending many Ancient Laws already. If we push any further, we won't just be breaking them, we'd metaphorically be wiping our asses with the whole document." Hypnos warned and Poseidon's expression turned stormy.

"I am well aware, Hypnos. And I know, just as well as you do, that by merely agreeing to this meeting, enough of the Ancient Laws have been broken that breaking a few more hardly matters in the grand scheme of things." The middle brother of the Big Three said in a dangerous voice, the current of the Lethe picking up in intensity, though he (and the river) settled down somewhat when Hypnos' gaze lazily slid from the Olympian towards his waters and back again with a raised eyebrow.

"Speaking of schemes, I know Hera's has planned something regarding the… others. I am unsure as to what, which is problematic enough, but I do know she has set her sights on my son, which makes it a hundredfold worse." Poseidon continued, getting a wince from Hypnos.

"Yeah, never a good thing when that woman starts paying too much attention to a demigod. Figures you'd want to send him away as far as possible then. Do you know she still hasn't held up her end of the deal from way back when I helped her during the Trojan war? Promised me a throne of gold, she did-"

"Excuse me!"

Now, most people would say interrupting an Olympian and the son of two of the eldest primordials in existence in their discussion was a monumentally stupid decision, and to be fair, Percy would have to agree with them on that point.

However, in his defense, he had gone most of his life by sticking to his dumb decisions and riding them out with a healthy dose of luck and stubbornness, to the point that it had won him (or his side at least) the second Titanomachy, so he figured it couldn't be too bad, right?

Stick to what you know and all that?

"Excuse me, but what is actually going on? Why do you need help, and why do you need my help?" Percy asked, swallowing down his nervousness as Hypnos' droopy eyes fully opened and focused on him, instead looking towards his father instead, being met with the same kind of ocean-green eyes that stared back at him in the mirror.

"Percy… what we are about to tell you… this has been kept a secret from your kind for a very long time and for a very good reason. If Olympos finds out that you knew what I'm about to tell you… you could be in a great deal in trouble. I could be in a great deal of trouble." Poseidon said in a grave voice.

However, with his father looking at him and with his closest friends at his side, Percy called upon the bravery that had seen him through one of the most brutal wars the Greek Gods had seen in centuries, if not millennia, squaring his shoulders as he took a step forward.

"So, what else is new?" he shot back, to the surprise of both gods, before Poseidon gave a rueful chuckle, shooting his son a lopsided grin filled with pride.

"Good point. Very well. Before we tell you why we've called you here, it's important that you understand this, a secret that has been kept from Camp Half-Blood longer than any demigod currently alive, kept from your kind for generations now… other pantheons are real as well." Poseidon gravely stated.

Silence hung heavily over Hypnos's island as-

"I knew it!"

-… as it was suddenly shattered by the victorious cry of Annabeth, who went white as a sheet as the outburst from her mouth finally caught up with the horror of her brain and she shuffled to stand slightly behind Percy as both gods gave her an odd look.

"Well, I mean… it makes sense, doesn't it? I mean, it's estimated that there have been close to ten thousand religions during humanity's time. It would've been preposterous to assume that the Olympian gods were the only ones to actually be real, especially given the connections there are to several older and concurrent pantheons and myths and then there was our fight with Mister Thorn, who was a manticore, which are actually originally from Persian mythology andI'llshutupnowsorry." Annabeth hurriedly explained, her waterfall of words petering out as she stood practically glued to Percy's side (who hardly minded).

Said demigod blinked a couple of times, before conceding the point. It would've been weird to think that their parents were the only gods that were real. It was just that he had never encountered anything or anyone connected to another pantheon (Mister Thorn notwithstanding, apparently) and so he hadn't questioned it.

"… I can see why your mother is so proud of you." Poseidon eventually conceded with a grin as Hypnos shrugged and went back to yawning.

Turning more serious, the God of the Seas continued.

"But indeed, there are many other pantheons. Some are… closer, to our own than others. Some may seem to contradict our very being, yet we all exist concurrently. Which is why this is not something that is exactly advertised, so to speak. How many religions do you think have a concept of a realm of the dead? Can you imagine if they were aware of all of them? What would happen if the lords of these domains started interfering with each other's realms? Even every zombie movie Hollywood has ever produced combined would not paint an accurate enough picture." Poseidon said gravely, getting three hurried, understanding nods from the teenagers in front of him.

Giving a satisfied nod that they had grasped the seriousness of the situation, he continued, hesitation creeping into his voice.

"Now, as I said, there are many domains that exist concurrently. The lords of these domains have a certain… sense, of their counterparts. I was recently contacted by one of my own, with an unusual request."

"It seems that, way out there off the edge of the probability branch – a conversation for never, that doesn't concern many of the gods, much less small beings such as yourselves – there exists a pantheon that has both a counterpart to me as well as Poseidon here. Or rather, a counterpart to my son Morpheus, who quickly realized how out of depth he was, so he contacted me and I in turn contacted Poseidon, who asked me to contact you and now here we all are." Hypnos continued, speaking continuously despite seemingly occasionally nodding off while standing up.

"In their world, rivers carry a great importance, as they did in many ancient cultures here and as they still do within our cosmology. The Styx that you've become… rather familiar with, for instance, or the Lethe behind you. Meanwhile, demigods often have important, powerful dreams. The more powerful the demigod, the more powerful the dream. Which of course is the domain of Morpheus and by extension under the supervision of Hypnos here. Because of this, their gods of Dreams and Seas managed to reach their respective counterparts in us and we decided to hear out their request. Which brings us back to you three." Poseidon explained further.

"What? Why? What was their request?" Percy found himself asking, captivated by the knowledge that, somewhere out there, a whole group of gods had asked to meet with his dad.

"They require a hero." Hypnos answered, before opening his eyes, pinning the three in place with a heavy look.

"That means you lot." He added dryly.

"Why us though?" Annabeth spoke up, having overcome her earlier embarrassment, her grey eyes gaining that familiar sheen when she was presented with a treasure trove of rare information.

"As we said, I was one of the easier gods to contact from their side. While I cannot go myself due to my ties to this plane, I can send my son in my stead. Which of course in turn means that I'll have to send the both of you as well, as I doubt he'd agree to go otherwise. Thankfully, the connection between me and my counterpart also means that they'll be able to reach me in order to bring you all back here when your task is done." Poseidon explained, a small smile on his bearded face as he glanced over the trio.

"You want me to go?" Percy asked, not sure how to feel about that.

He knew that it (probably) wasn't the case, but some small, traitorous part of him, the part that had never quite gotten over the fact that his dad hadn't been there for him during his earliest childhood, that had abandoned his mother to the likes of Smelly Gabe, whispered in his mind that this was simply a ploy from his father to finally rid himself of his trouble-making son.

Said poisonous thoughts died an immediate and ignoble death when Percy suddenly felt a heavy calloused hand rest on his shoulder. Looking up in surprise, the demigod locked eyes of a similar hue with his father, who now openly wore a proud smile.

"Indeed. From what I could gather from their message, these gods are desperate, Percy. An ancient evil, thought destroyed, has endured all along and has begun to once again grow in power. I'm sure that must sound familiar to you. However, unlike when you and your friends stood against Kronos, these people aren't prepared to face their greatest enemy, not yet. They need help, Percy. They need a hero, now more than ever and I cannot think of any hero who is greater, or who I'd trust more… than you." Poseidon spoke softly, but warmly.

His chest suddenly feeling tight, Percy managed to speak up with a grin nonetheless.

"You're just saying that 'cause you're my dad."

"Of course, that's my job as a dad, isn't it?" Poseidon responded with exactly the same kind of grin fixed on his son's face, before continuing in an earnest tone.

"Yet that does not diminish what I said in the slightest. I trust you, Percy. You'll make me proud, I just know it."

Again, Percy's chest felt tight and all he managed this time was a choked out "thanks" before his entire body suddenly felt tight as Poseidon wrapped him in a hug.

"Just… be careful. In some ways, their world is more dangerous than the one you'll leave behind. While their plane may hide you from Hera's gaze until your return, beware of great powers over there as well. A demigod is a worthy prize in any world." Poseidon warned, before letting go of his son and stepping away, ignoring the curious look Hypnos sent him with a weathered ease.

"… Okay. If you think that I can do this… If these people have their own Kronos-type situation going on and they're even worse off than we were… then okay. I'll do it. I accept the quest." Percy stated.

"Well, that's just wonderful. Now, off you go, they're a bit in a hurry-" Hypnos began, before Percy interrupted Death's twin for the second time in less than fifteen minutes.

Strangely, he didn't really feel bad about it.

"I said that I accept. But I don't speak for my friends. This is their choice as well." Percy stated firmly, trying (and only somewhat succeeding) to ignore the curious look Hypnos sent his way by turning around and facing his friends.

"Well, what do you guys say? You don't have to go. This sounds dangerous, so I'll understand if-"

"You really are a Seaweed Brain, aren't you?" Annabeth interrupted him, her tone dry but her eyes shining with mirth as she finally relaxed, once again pocketing her baseball cap.

"You really think I'm going to let you run off to another world without me? Who's supposed to get your butt out of trouble if I'm not there?" she responded with a grin.

"Who says I'm going to get into trouble?"

"It's you Percy. You always get into trouble."

"… ok, fair enough."

The two shared a grin as they held each other's hands, before Percy glanced at his best friend, who was still hopping from one hoof to the other in place as he nervously looked at the two very powerful gods standing mere meters away.

To Percy's (slight) surprise and (great) worry, Grover's habit of eating when nervous had caused the young Satyr to stand there on the shore of the island with half a dozen poppy-flowers hanging out of his mouth. Thankfully, the crimson leaves didn't seem to have any effect on the goat-man, who looked from Percy, to the yawning darkness of the cave, back to Percy again.

Eventually, he gave in with a pained sigh.

"Ah, whatever man. It's been months since the war, I guess we checked out all of our non-mortal-danger days already, huh?"

"That's the spirit."

Turning back towards his father and Hypnos, Percy gave a confident nod that was only partially faked.

"We're in. When do we leave? And, uhm, also, how do we leave? Do we just… wake up there? 'Cause this is a dream and stuff…"

"It's quite simple actually: just walk through the entrance of this cave. Their cosmology and the interior of my domain have some surprising commonalities: forging a passageway turned out to be less impossible than initially thought." Hypnos replied, lazily waving towards his home with one hand, the other one held in front of his yawning mouth.

Looking at that wall of near-solid darkness, Percy swallowed a lump in his throat that sadly had nothing to do with the gooey feelings he felt when his dad had hugged him.

"Come, son. Be brave. You can do this." Poseidon spoke up in a warm, confident tone and then Percy did have to swallow a gooey feelings-induced lump in his throat, giving a nod towards his dad as he gave Annabeth's hand a firm squeeze, his courage bolstering when she squeezed him back.

"Alright. Another plane of existence, here we come." He muttered, feeling his friends behind his back as he took a deep breath, before he steadily walked towards the entrance of the cave.

All he caught from the corner of his eye was Poseidon's expression, a complicated mixture of concern and pride on his weathered face, before the veil of darkness fell around them, muting all sounds and sealing away all light.

Percy almost stumbled, before his signature stubbornness made itself known and he forced himself to keep walking, to ignore the blackness surrounding him and suffusing his every sense as he just kept setting one foot in front of the other.

'Come on, Percy. You've faced worse. Probably. Can't think of anything specific, but with the way your life has gone until now, there has to be something. Just do what you've always done: keep moving. Just keep moving. Ignore the fact you can't even tell if you've got your eyes open or closed, just. Keep. Moving. Ignore everything else, ignore the whispers and just focus on-'

Wait, whispers? Slowing his pace, Percy tried to focus his hearing. If it weren't for the fact the silence that had fallen around them the moment they had entered Hypnos's cave had been utterly absolute, he probably wouldn't even have noticed the faint words seemingly carried on a whisper from very (very, very, very) far away.

"Nîn o Chithaeglir lasto beth daer; rimmo nín Bruinen dan in Ulaer!"

The words sounded strange. It was no language that Percy had ever heard, of that he was certain, but they sounded… nice. Strong even. There was a message in there that somehow spoke to the Son of the Sea. A plea to the waters of the land, a call upon old powers to defend those in need.

Percy's vision, until now occupied by nothing but the deepest black, was filled with the picture (or was it real-time? After so lang in the darkness, it was a little bit hard to tell) of a raging river, of steep cliff sides and of… horses?

'Oh… I can work with this.'

Arwen had had a rather eventful day, to put it mildly. She had known the plight of her Aragorn before she set out from Rivendell, against her father's wishes, but even her many years in Middle-Earth hadn't prepared her for when she found him in the wilds, in the presence of four scared Hobbits no less, one of which had been gravely injured.

She could feel the Darkness pouring from the weeping wound in the little one's side and knew what evil he carried around his neck, yet she felt no hesitation when she set herself upon Asfaloth's back, taken the light (the far too light) Hobbit from Aragon's arms, instead merely feeling a pang of worry of what would become of him, before reaffirming to herself that, the further she got away from him, the safer he'd be.

And the servants of Sauron had proven her correct when, one after the other, they appeared from the underbrush like spectres, each one getting closer than the last, to the point that she could hear the creaking of their saddles, the aching noise as their armored plates grated against each other, the deep bellowing breaths of their steeds as they were spurred on beyond what mortal horses should be capable of.

So great had the power of their dark lord become, the mounts of the Nine were capable of not merely keeping up with her and Asfaloth, but even gaining on the noble steed, lent to her by Glorfindel himself, a thing that by all rights should have been impossible.

But Arwen could not ponder on the possible and the impossible as she crossed an undeep part of the Bruinen, trusting Asfaloth to find his way through the rounded stones and sudden, small rapids. Because, even as she eventually made it to the far shore, finally within the far borders of her home, the Nine assembled on the other bank, a collection of black cloaks, deadly swords and mindless hate.

"Give up the Halfling, She Elf." One of the Riders spoke, its voice sounding like the dying gasps of a thousand Men, its empty hood fixated on her, as all were.

Many would have complied, the cold terror seeping from the Nazgûl sapping their will and eating away at their courage, but there was strength in Arwen, who called upon the might of her forebears to remain standing tall in the face of their hatred. She reminded herself of her fabled ancestor Lúthien, with whom she was so often compared, of her grandmother Galadriel, wisest and amongst the most powerful of all the elves and of her father, Elrond Half-Elven, and his unwavering dedication to the welfare of her people for thousands and thousands of years, the protector of the Last Homely House.

Considering their great deeds, and the helpless youth in her arms, rattling each breath as if it were his last, what other action could Arwen Evenstar take, than to pull her sword from its sheathe, lift it high and proclaim that she would do no less in the face of evil than her forebears had done time and again.

"If you want him, come and claim him." She called back in challenge, her eyes steadfast and unwavering as she looked the Nazgûl in its empty hood.

Incensed at her fearlessness, the steeds of the Riders stamped their hooved feet, gravel and water coming up in sprays as the Nine unsheathed their blackened Morgul blades as one, a wall of steel and the promise of a fate worse than death.

Steadily, overriding the instinctual fears of their mounts, the Nazgûl forced their horses into the shallow depths of the Bruinen, slowly, but inexorably, making their way towards the lone elf. Brave though she may be, and more skilled with the blade than many would give her credit for upon first seeing her, Arwen conceded that the strength of her sword arm alone would not safeguard Frodo here.

But here, began the lands of Rivendell. Here, she never was truly alone.

"Nîn o Chithaeglir lasto beth daer; rimmo nín Bruinen dan in Ulaer." She whispered underneath her breath in Sindarin.

It wasn't a spell, not as the Istari and even her grandmother were capable of, not exactly. It was a plea, both to the lands and to the echoing strength of her forebears to come to her aid. Not every elf could hope to make such a plea and have it be heard, but she was the daughter of the Lord of Rivendell. To her, the river answered.

"Nîn o Chithaeglir lasto beth daer; rimmo nín Bruinen dan in Ulaer!" she called again, louder this time as she felt the way the land responded to her need.

And then her eyes widened in shock as she felt something else respond as well. The river receded, as it would have, but the very earth underneath Asfaloth's feet began to rumble with a great power, a power not of the Bruinen itself, an old and great river though it may be.

The very air itself began to feel charged with power, as if a Maia were standing right there in their midst and both the Nine Riders and their black steeds were clearly nervous as the unknown presence grew.

And then said presence was heard as well, a terrible roaring sound like a waterfall that set the air in Arwen's lungs to tremble, as around the far corner of the Bruinen from where it came down from the mountains, a massive wall of water swept forth.

Arwen didn't know what a tsunami was, but she, like all Elves, knew of the tale of how great Beleriand was sunk at the end of the War of Wrath, the entire continent sliding underneath the ocean waves. She imagined that the sight must have been much like the scene approaching her now, merely on a larger scale.

A wall of water, great and dark and churning, seemingly large enough to swallow a city (or at the very least a decently sized Balrog) rushed towards them at speed rivalling even the fastest of Maeras. The Nazgûl, caught off guard and already in the river's unyielding grip, had nowhere to run.

The shapes of horses, and riders upon them, formed from the swirling foam at the waves' fore, and to her surprise Arwen saw that upon the first three horses sat three people, made of flesh and blood (or so she presumed at first, after all, who knew what kind of being could ride the terrible wrath of Bruinen like so?).

Two of them appeared as children from the race of Man, a blonde girl and a dark-haired boy, their faces showing the both the youth of their years, as well as how experienced in hardship those years had been. They were approaching as fast as the wind, yet Arwen was still stricken by their unusual eyes, a stormy grey and a deep sea-green, filled with power. Accompanying them (or rather, desperately clinging onto the third horse in their vanguard) was a man with a skin like none Arwen had ever seen before, a dark brown like the bark of an old tree. More unusual than his skin however, were the horns on his head and the hooves on his furred legs.

The water underneath the Riders churned as they tried to reach the safety of the shore to no avail, seemingly caught in the grip of the flowing waters, though as the child at the front of the oncoming wave summoned a three-pronged spear made from the river itself, Arwen doubted the shore would've been any safer for the servants of the Eye.

"CHARGE!" the Man roared in a battlecry, the watery riders following him seemingly roaring alongside him as Bruinen did its name Loudwater justice, the river itself thundering with a wall of sheer noise as it made its displeasure towards the intruders known.

Many of the wraiths cried in fear, though one tried to aim its blackened blade towards the oncoming horde, but neither cowardice nor spite prevailed, the youth swinging upwards with his trident, the river underneath the Riders immediately following his command as it seemed to be pulled out right from underneath them. Many of the horses lost their footing. Many of the Riders lost their grip. And like an avalanche from Caradhras itself, tonnes of water, the very fury of Bruinen itself, slammed into the Nazgûl with a vengeance, blasting them apart and tearing them asunder.

Bruinen rumbled as the host of watery riders continued onwards, washing the filth of Mordor away as the water level of the river steadily returned to its usual self. But three horses remained, each one large enough that the top of Arwen's head, seated upon Asfaloth as she was, only reached their flanks. Shocked and unable to find the words, she looked up as the young man steered his water-horse forwards, stopping shortly before the shore on which Arwen stood.

Despite having to look down at her and despite having just decimated Sauron's most feared agents with a power that Arwen at first mistook for one of the Ainur, possible even a Vala, the youth had an awkward expression on his face as he addressed the Elven princess.

"Uhm, hi? My name is Percy Jackson. Your gods asked for my help?"

While Arwen stood both motionless and speechless, Frodo managed a rather appropriate response in the face of such a claim:

He fell right off Asfaloth's back and straight into the land of blisfull unconsciousness.

AN: So I wrote this for an Emerald Library quite a while ago, but realized I never actually uploaded it to my own profile after the challenge had been completed, so here you go. I might expand on this in the future, there are some interesting ways to split up the PJO trio among the LotR cast and have them influence the story/world.