Usually, 'cramped' would be the last word to describe Poseidon's throne room. He was a god who hated enclosed spaces, so it was a large, open room made of colorful coral. But today was a different matter. Poseidon paced back and forth, ranting to his wife. With every step, the walls seemed to close in a little bit more.
"Two quests now! Two, and Zeus won't even let me pop in to say 'hello, great job' and warn him about the Golden Fleece waking up that girl. I mean, he accuses ME of playing favorites. He just wants his daughter back, and doesn't want to do anything to mess that up! Besides, I wouldn't mess it up, I'd just let Percy know, so he isn't completely blindsided! I mean, really. He's a stubborn idiot who only cares about himself. He must have hit himself with a lightning bolt recently!"
Amphitrite waited patiently until her husband ran out of steam. Unlike other immortal stepparents (cough Hera cough), she didn't really mind her demigod offspring. She wasn't happy about them, but she didn't hold grudges against them. Besides, it wasn't Percy's fault he existed. Amphitrite enjoyed watching Poseidon interact with his mortal son. Triton had, in the past few centuries, become less of a son and more of a military commander, and she knew Poseidon missed him.
Several hours later, Poseidon couldn't think of any more insults. He flopped down on his throne, exhausted. "Maybe I should just go visit him. If I'm quick, Zeus might not notice." He muttered.
After millennia married to him, Amphitrite knew an opening when she saw one. "Instead, why don't you write a letter for Hermes to deliver to him? Zeus told you specifically not to talk him, but not anything about writing a letter, right?"
Poseidon straightened up on his throne. "You know, that's not a half bad idea." He commented softly. "In fact, that's a brilliant idea! Thank you, thank you, thank you!"
Amphitrite smiled. He was one of the oldest gods, yet he sometimes acted 5 again. She supposed it was because his childhood hadn't been exactly a happy one- what with being swallowed by his own father and everything.
She was yanked out of her thoughts by Poseidon running out of the room to grab a pen.
"So, how should I address it? Dear Percy? Or should I leave out the dear?"
Amphitrite thought a second. "Skip it for now, come back to it."
He nodded. "Good idea." He began to scribble, dictating to himself as he went. "Sorry I can't talk to you in person, but Zeus is a vlakas right now. No," he scribbled that out. "I'm prouder than you can imagine. 2 successful quests in 2 years!" He nodded to himself. That was a good way to start. "Brace yourself, though. Apollo says the healing power of the fleece may bring back Thalia. If this happens, it will complicate the prophecy. You MUST be the one it speaks of, so take the Fleece off the tree!"
"Poseidon," Amphitrite warned. "If Zeus sees…" She left the threat dangling, but he saw her logic. Sending word to his son was important, but not worth being blasted off Olympus.
"OK," he scribbled out the last few lines. "Brace yourself, the Fleece may have far-reaching complications." He glanced at Amphitrite. "That good?"
She weighed the risks in her mind. Chances are, Zeus would never see it, and Percy deserved to at least have some knowledge of the threat. "Very well. Is there anything more?"
Poseidon shook his head reluctantly. "No, I'd better keep it brief."
He folded the paper and tucked it in an envelope quickly formed out of a wave.
Neither deity saw the words rearrange on the paper, all vanishing except two: Brace yourself.
As Poseidon flashed out to Olympus to find Hermes, Amphitrite happened to see the Fates hidden in a nook of the throne room, serenely knitting, as if they didn't have the lives of everyone Amphitrite loved literally in their hands.
As she hesitated, debating whether to talk to them, they caught her eye, winked simultaneously, and vanished.
Because I doubt Poseidon would take the trouble to write a letter to his only mortal son, then write 2 words. Also, in mythology, Amphitrite is one of the nicer immortal stepparents. She just had a lot on her mind when Percy met her... R+R, please!