A/N: I liveeeeeeeeeee! It's short and sweet but it's better than nothing I guess?

Chapter Twenty
The Plot Thickens

Naphos followed Poseidon to the air/water barrier. They halted several body lengths from the barrier itself to prevent eavesdropping.

"Sire, I insist upon a different course of action," Naphos said with an edge of desperation in his voice. "It is not wise to put yourself in a position of weakness. If your brother sent the poison, you could be walking into a trap."

"I hear you, Naphos," said Poseidon, reaching out to clasp the Merman by the shoulder. "If my brother wanted to poison my son he has had multiple chances. I leave Percy with him unsupervised and he has never so much as looked cross-eyed at my son. It does not make sense for him to do this now."

Naphos' shoulders relaxed but only just. "I only wish you could take some backup, my lord," he said on an exhale.

"Unfortunately my brother is not that laid-back," said Poseidon with a wry twist of his lips. "I doubt he will mind me visiting aside from his usual snappy rejoinders, but he hardly lets just anyone go waltzing into the Underworld.."

Naphos nodded, once, and watched the king stride away. He made it through the barrier, said a brief speech distorted and hard to hear from where he was watching, and then disappeared in an explosion of bubbles.

"Good luck, Poseidon," he said, and offered up a prayer to whatever Gods may be listening that his favorite god would be successful in his mission.

A little boy's life depended on it.

Poseidon made quick work of travelling to the surface world. His head broke the surf on the California coast long before sunrise. If nothing else he was thankful for a respite from the worry someone might spot him, even through the Mist.

This early there were no people around to see him striding from the surf. He startled a few crabs from their nightly activities but otherwise the beach was empty. Shaking sand out of his sandals, he strode with a purpose towards the brother he loathed the least.

LA was a dreadful city and he despised it, moving as fast as possible towards the entrance to his brother's realm. A faint rain was falling and a strong wind carried the scent of the ocean. The seas were rough and stormy but his wrath was more tamed this time around.

For now.

All the same, Charon gulped audibly at the sight of him.

"I wish to speak with my brother," he said to Charon, rather unnecessarily, he thought. Why in Olympus would he be here otherwise?

"Of c - course, Lord P - Poseidon," said Charon, stammering over the words and ushering him to the elevator.

Poseidon twirled his trident in his hand while he thought. What kind of poison could have put his son out of commission? His healing would have handled the majority of poisons, even ones deadly to humans. Godly blood was a great immune booster. It did not protect from everything but it was a good first line of defense against most common dangers.

Hades could not have done this. It made no sense. The only way it made sense was if someone was attempting to frame his brother; if the poison was even linked to Hades at all. But why would someone want him to think Hades had tried to hurt Percy? All it would take was five seconds watching Hades and Percy together to see that the God of the Underworld was fond of the child.

The whole thing was a disaster.

At the moment, all he wanted was to shed blood. But first he needed answers.

When the descent completed the elevator dinged cheerfully. Charon ushered him out to the boat and Poseidon handed him four coins.

"Two for this time, two for last time," he said, gruff.

Charon looked surprised but he pocketed the fare without further comment. The ride across was silent but somehow not awkward. Charon seemed to sense that he was not in the mood to talk but had picked up on his more docile temper this time around and was not as tense.

Last time he'd scared the poor fellow. He'd been a bit angry at that moment but had tried hard to not take it out on the lesser god.

"Thank you," said Poseidon, nodding at Charon as he stepped off the boat to the bank of the river Styx. Cerberus gave three happy barks and he reached up to scratch the great brute beneath his chins. The guards made no move to stop him as he slipped through the gate and into the Underworld.

Hades was waiting for him in the throne room with Persephone beside him.

"Hades, Persephone," he greeted them, leaning on his trident and offering them a respectful nod.

"Don't bother wasting time on pleasantries," said Hades with a heavy sigh. "What is it you want this time, Barnacle Beard?"

Poseidon could respect his brother's talent for getting directly to the point. He held Hades' eyes and said, "Did you poison him?"

Hades looked taken aback for precisely one second before his expression switched to one of outrage. "Excuse me?" he said in a voice that was dangerously low as he half-rose from his throne, his demeanor nothing short of threatening.

"As I suspected," said Poseidon as he relaxed fully. Hades was good at lying but had never been particularly good at lying to him. The outrage had been real. "I had to be sure."

Looking confused now, Hades sank back into his throne and lifted a hand in the universal gesture to stop, barking, "He was poisoned?"

Behind him, Persephone had stood from her throne and was frowning as she looked between them. She had not yet interacted with Poseidon in the Underworld - their encounters had always been restricted to solstice meetings - and by her expression she had not expected to find him here, ever, and she had no idea who they were talking about.

"Not two hours ago," Poseidon said. He rubbed his eyes and eyed the throne Persephone had vacated but opted to stand instead. If he sat now, he may never stand up again from the sheer weight of exhaustion on his shoulders. "One of my advisers suggested I come to you and ask if you had seen the poison before."

If anything, Hades looked even more outraged than he had before. "Your adviser thinks I poisoned him?"

"I said nothing of the sort," said Poseidon, shooting his brother a look. "They thought perhaps it is a poison that comes from Tartarus. The healer is at a loss."

Hades frowned at that, considering. He dropped his face into his hand, long fingers curving around his cheek. He wasn't looking at Poseidon anymore; he was looking through him, deep in thought. After a long moment, he came back to himself with a small shake of his head and asked, "Is he still breathing?"

Poseidon nodded the affirmative. "The healer says he is remarkably strong, considering."

"If he's still breathing, the poison likely is not from Tartarus, my lord," Persephone broke in as she stepped up beside her husband's throne. "I do, however, grow many poisonous plants in my own garden. I may be able to help."

The brothers looked at each other, equally taken aback.

Persephone was fascinated and looked between the brothers. There was some kind of silent communication coming on that she could not decipher. Hades had a small frown - the closest he came to outright worry - and Poseidon looked grave and stressed. As she watched, Poseidon lifted his dark eyebrows and tilted his head towards her. In response, Hades nodded just enough to be noticable and lifted his shoulders in a small shrug.

Whatever that meant must have been a signal, because their dark eyes turned back to her in erie unison. It made the hair on the back of her neck stand up. They didn't' look much alike but in that moment she had no doubt they were related.

Poseidon took one step towards her, both hands curved around his trident. She gazed back at him and couldn't figure out his expression other than the worry in the tilt of his mouth.

"Tell me everything," Poseidon said.

Beside him Hades just nodded in encouragement, with a hand gesture she interpreted as go for it. Persephone took a deep breath, smiled, and proceeded to do just that.

/

Persephone had an impressive array of plants in her famous garden. She walked along and explained each and every poison - hemlock, poison ivy, nightshade, foxgloves, Lily of the valley - and their side effects.

Poseidon listened raptly as his brother hovered silently at his shoulder, present but not interrupting or interfering. It was likely he knew all of this already but had chosen to let his wife take over. None of the poisons she described seemed to include only raging fever and unconsciousness.

"He has been unconscious since he was stabbed," he said to her seriously, reaching out to trail his finger along the delicate white flower of a Lily of the valley. "Other symptoms include sweating and a high fever."

"If this person is Atlantean, their bodily anatomy is different than that of a human or a God," Persephone told him matter-of-factly, gently fingering a leaf of a hemlock plant. "Those symptoms could be any one of these poisons." She waved a hand in a gesture that encompased the entire garden. "Is there anything coming from the wound?"

"Dark lines," said Poseidon. "They have it bound with the knife still inside until a surgeon can determine the best way to remove it without causing further damage. The knife is approximately this long," he balanced his trident on his shoulder and held his hands nearly six inches apart, "and judging by the hilt is curved and made of what appears to be a whale bone."

"I am not a healing goddess, Lord Poseidon," said Persephone as she twirled her fingers around a different hemlock leaf. "I'm afraid all I know are the symptoms."

Poseidon inclined his head as his heart sank in disappointment. "I thank you for your time, Lady Persephone," he said and meant every word. He'd always been fond of his brother's wife even if her mother often drove Olympus to distraction with her raving about the benefits of cereal.

Persephone looked between the two gods: Poseidon, who looked exhausted and stressed, and Hades, poorly attempting to hide his own worry. Whoever this mysterious "he" was, they both clearly cared about him and were trying hard not to give her any clues as to who he was.

Very badly; they were being painfully obvious in their subterfuge. She smoothed her hands along her dress and smiled. Sooner or later she would find out who the mysterious "he" was. In the meantime, her husband's frown was rather loudly broadcasting that he'd like to be left alone with Poseidon.

"I will leave you two to catch up," she said, putting her hand on Hades' chest so that she could stand on her tiptoes and kiss him on the cheek. Hades offered her a small smile - merely the uptick of the corner of his lips - but it was good enough for her. She offered a respectful nod to Poseidon and exited her garden through the nearest archway.

She dared to glance back only once and it was to see her dear husband and his brother interacting in a way she'd never seen. Poseidon was gripping his trident, head bent to the floor, and Hades had one of his shoulders in a firm grip and was speaking to him in a voice too low to hear. Their dark heads were bent close together and unless her eyes deceived her, there were tears tracking down Poseidon's scruffy cheeks.

Whatever was going on, their strange interactions sure helped to piece together Poseidon's epic hissy fit and subsequent poor temper at each and every solstice since the now-infamous blasting of arctic water into Zeus' face. It had not escaped her notice that Hades' attitude towards his brother had softened significantly in the last handful of years and that he mysteriously disappeared hours before necessary on solstice days. He thought she hadn't noticed but she certainly had.

"Very odd," she murmured to herself, picking a pomegranate and strolling back into the palace to mull over possible answers to her new mystery.

/

"That kid is as stubborn as they come, Poseidon," Hades told his brother fiercely. "He inherited every single fiber of bullheaded idiocy in your body, believe me. A little knife will hardly fell him."

"I know he is stubborn," Poseidon said gruffly, wiping an angry hand across his eyes. He absolutely hated showing weakness to anyone but Amphitrite but for some reason he wasn't uncomfortable doing so with Hades. "But Hades… he is so small."

Hades merely nodded because it was true. Eight was small for mortals, though the boy's personality sometimes made him seem older than he was. Percy was an old soul - a goofball at times, yes, but he knew for a fact that Percy's soul was not on it's first trip to Earth. It was in his eyes. (He had a sneaking suspicion whose soul it was but he'd keep it to himself for eternity).

"Have faith," he suggested gently. He supposed it was a win that Poseidon wasn't shaking the Underworld apart this time but he hated seeing his brother so defeated. "I am certain they will find the cause and the true perpetrator."

"Orryn thinks that he had help," Poseidon admitted, sinking to sit on the nearest bench. They were scattered amongst the garden along with a handful of statues that appeared to have come from Medusa. He pushed the observation to the side and rubbed at his beard absently. "I racked my brains but cannot come up with someone who would want to hurt him."

Hades sunk to sit beside him, tapping his fingers on his knee. "I suppose it could be Oceanus, but it's not really his style." Oceanus generally sent monsters just for something to do, not out of true malice for Poseidon. Subterfuge wasn't his style.

Poseidon grunted in agreement. "Orryn also thinks it's odd that the poison is so hard to identify. He suggested Tartarus and after I assured him you would never do such a thing, he suggested that perhaps someone was trying to frame you."

Hades' eyebrows shot into his hairline. "How rude," he deadpanned.

"It might have worked," Poseidon muttered, "Eight years ago."

A shoulder shrug and a grunt were Hades' answers. Eight years ago it probably would have worked, actually. Poseidon had a tendency to stab first and ask questions later. The Hades of eight years ago would have responded in kind and it could have (possibly) led to civil war.

But he wasn't the Hades of eight years ago; he was the Hades of now, and he cared about that boy more than he would ever admit even under pain of death. If someone was trying to kill him he was going to find out who.

"It could very well be from Tartarus, Poseidon," Hades said softly after long moments of companionable silence. "I would have to see to know." He cleared his throat and rubbed his hands together. "Even I do not make a habit of strolling around down there."

Poseidon grunted. He knew full well that Hades tossed creatures into Tartarus as ordered but hardly ventured there himself; it was a pit, quite literally, that resembled the Hell the human Christians went on and on about. It was a prison for the Titans and the worst of the worst. Tartarus was also a Titan who had had a physical form, once, but not for centuries - he still served as the guardian of the pit who bore his name. Tartarus was as deep beneath the Underworld as Olympus was above earth - or so legends said.

If the poison was from Tartarus, well. The odds of Percy surviving it were slim to none. But on the other hand, he'd likely be dead by now if it had been from Tartarus.

"Most likely it came from the surface world," Hades concluded, patting his brother on the shoulder. "I hope Orryn's agents can determine a source."

"Me too," Poseidon murmured, and the brothers lapsed into companionable silence.

On the western coast of Florida under a blanket of fog, a tangle of mangroves was calm and quiet. It was a popular meeting place for sharing information between Surface and Subsurface, and as such, there was one Atlantean waiting in the shallows. The lack of moonlight made for poor visibility, but anyone with ears would be able to hear someone coming.

Ayla Taragon had been in the Aegis since she'd come of age but had never been tasked with a mission of this importance. She and four others had been sent in secret to the Surface in search of an antidote to save Poseidon and Amphitrite's young son.

It was far from a standard mission. She was sure others had been sent, but she and her team were actively hunting down venomous creatures that may have sickened the child.

She was standing in the shelter of a Mangrove, waiting for a distant contact of Lord Orryn's - a man who was Atlantean, but had chosen a life on the Surface. Personally Ayla couldn't fathom such a choice but she'd been assured he was the real deal. Out of habit she was tapping her index finger against her sword hilt and pondering the situation at hand.

Aside from some overly-friendly Manatees and a couple of curious young sharks, she was alone in the mangrove.

Swishing water unlike that of a wave pattern alerted her to another presence approaching from the shoreline. Though the mist the figure of a man slowly solidified, until he was a handful of paces away from her, moving at a pace that meant certain collision if she didn't get out of the way.

"Halloran?" she called out, alarmed, as he seemed to stumble and fall. "By Poseidon, did you run all the way here?"

Ayla caught him but only just, bracing him and lowering them both into a crouch. His chest was heaving as though he'd just run a great distance. Unsure what else to do, Ayla splashed water to every part of him she could reach. It seemed to help.

The red-haired Atlantean sized her by her armor and hauled her towards him until they were nose-to-nose, startling her so badly she nearly stabbed him.

"There is a traitor in the house of Poseidon," he gasped, and then promptly lost consciousness.

Ayla stared at him in silent horror, gently propping him against a mangrove tree as she mulled over his words.

There is a traitor in the house of Poseidon, he'd said. Not House, implying the family - house, as in where they lived.

Where the royal family lived. Where Percy lived.

There is a traitor in the house of Poseidon.

Whoever had tried to kill Percy was right beneath Poseidon's nose, hiding in plain sight.

Sorry if it's terrible ¯\_(ツ)_/¯