Nico POV

"Are you sure we're in the right place?" I asked Percy uncertainty. Without missing a beat, he nodded his head, still marching forward.

"I don't know if I like this, Percy," Piper said uneasily. In a typical fashion, he simply waved his hand, as if her concerns were minor.

"Nonsense," Percy scoffed. "Me and Nico have visited this immortal many times!"

"If by many times you mean thrice, one where you almost met a fate worse than death, then sure," I frowned. Unfortunately, the reminder of his previous fate didn't sway the young god, and he kept skipping down the dark passage with an air of confidence that both impressed and unnerved me. I know I should trust Percy, being one of my closest friends, but the fear of whatever could happen to me still gnawed at me, like a persistent itch that refused to be scratched, which let me tell you, is a horrible feeling.

Currently, the three of us were trudging through the dark cavernous tunnels of the Underworld, Piper and Percy leading the way, weapons drawn. The shadows seemed to dance around us, whispering in secret language only they could understand. Percy reached a fork in the pathway and froze for a moment, as if he was trying to remember which way to go. He frowned, before going down the left pathway. I didn't like this part of the Underworld. It had been one of the few parts that even Hades disliked. Before Percy had the brilliant idea to come here, I never would've dared to

As we continued walking, I couldn't help but feel a sense of dread wash over me. You know it's bad when Hades's son himself is scared, I thought ironically. The air was thick and musky, with a cold, eerie silence, broken only by the sound of our footsteps echoing off the walls. The darkness was oppressive, with their only light source a couple of torches they'd bought from the Overworld. I couldn't see them, but I could hear the monsters growling in the darkness.

Naturally, Percy was oblivious to all this, striding ahead with confidence. His sea green eyes flickering with gold as he scanned the shadows for any danger. His black hair was tousled by the cold, musty air, but he didn't need to notice. Percy was much more focused, determined to reach this god. He had his staff out, using it as a hiking stick. I winced every time the cold, metal stick hit the ground, the sound vibrating across the tunnel. One thing that still shocked me was how good Percy managed to look without trying. His golden robes suited him, and even though his face was grimy and his hair was oily, I knew that if Calypso was here, she would've been giggling with Piper about how hot he looked to her.

Speaking of Piper, she was walking beside me, her expression tense as she glanced around nervously. Like me, and unlike Percy, she seemed to sense something hidden in the darkness as well. Her long brown hair was pulled back in a braid, and her eyes were sharp, studying every detail of our surroundings. She also had her fingers wrapped tightly around her knife, ready to attack or defend at a moment's notice.

As for me, I kept my head down and tried to stay as quiet as possible. My aura as a son of Hades was strong in the Underworld, and the last thing I wanted was to draw the attention of any wandering spirits or monsters. As we followed Percy, my black hair kept falling across my face, and I was forced to push it back irritably, something that made Piper laugh gently.

It had been just over a few hours since they had left the rest of the Revenant on Mount Olympus. Percy had been eager to leave as soon as possible, and when his mind was set on something, there was usually no point trying to change his mind, not like we could be asked either. Once we were off Olympus, Percy quickly flashed us to the entrance of the Underworld. None of us wanted to deal with Charon, specifically Percy, so we went to the Cave of Sybil instead, which had also moved from Turkey to America, following the flame.. From there, I navigated us down to the Underworld, which apparently wasn't as easy as either of us remembered it to be. After that, everything was Percy's job, as we slowly weaved in and out of caves, each one narrower than the last, until finally, we were here right now, still stuck in a cave, with me and Piper feeling overwhelmingly claustrophobic.

"Percy," Piper whispered.

"What?" he asked very loudly, causing me and her to shush at him loudly. He only raised an eyebrow.

"I don't want to act like Donkey from that Ogre film," she began nervously. "But are we there yet?" Lightly, he chuckled. I mean, could he really blame us? The two of us were exhausted, our feet sore from the walk. We didn't understand how Percy had it in him to keep walking, let alone skip along with excitement. It's not even like this immortal was anything exciting either.

"Listen carefully," he said. "Do you hear that?"

"Honestly all I can hear right now is the sound of my rumbling stomach," Piper groaned, clutching her belly for effect. Percy rolled his eyes.

"You're worse than Nico when it comes to food," he snorted. Piper shrugged.

"I might be, but we all know no one's worse than you." For a moment, Percy seemed to study her, his golden-green eyes narrowing, before letting out a chuckle at her antics.

"That is the sound of a river, a very quiet one, but a river nonetheless."

"Percy, I really hope your mad plan isn't to visit Styx and call your favour in, because as you pointed out a few weeks ago, Styx has been captured, which is partly why oaths on her name aren't exactly binding at the moment." He rolled his eyes, clutching his heart in mock pain.

"Oh you wound me, Piper," he said. "Did you really think I would lead you down, only to realise the person we were searching for isn't even here?" Upon seeing both of our faces, he muttered out a quick, "On second thoughts, don't answer that."

It wasn't much more of a trek before the cave began widening, forming a sort of clearing. As we walked further in, the ground beneath us gradually sloped downwards. Now I could hear the quiet rush of water Percy had been talking about.

At first glance, it appeared to be an ordinary river, the kind that you might find anywhere else in the world, but no, this river was very special. The river was clean and deep, so deep I couldn't begin to see where it ended. The other strange thing was this river wasn't blue or black. No, this river was yellow, flowing with serenity.

"The River Lethe," Piper breathed, her face turning pale. Oblivious to this, Percy's grin grew even wider.

"Oh yes, me and Nico have many fond memories here," he chuckled, causing me to glare at him,

"If by fond memories you mean when you were attacked by the Keres and nearly died about seventeen times before Iapetus saved you-"

"You WHAT!" Piper shrieked.

"Oh yeah, it's a sick story that happened just before the Second Tiatanomachy," I began grinning devilishly, ignoring Percy's twinge of annoyance. "So during Christmas, Persephone had some weird idea to make an illegal sword, and then sent me, Percy and Thalia on a wild goose chase to get it. Then, we run into the Keres and Percy gets poisoned. Anyway, me and Thalia patched him up as best we could, and we kept going. Then, we reach Lethe, and of course Iapetus is there, but he's actually evil. I know right, mega plot twist. So we're all fighting and with the remainder of his energy, Percy drags Iapetus into Lethe, and he forgets his memory. We rename him to Bob." Piper rolled her eyes, but seemed to focus on one thing he said.

"Wait, how come Percy didn't lose his memory?" she asked, furrowing her eyebrows.

"He can make himself dry underwater, remember? Here, take a look yourself." I indicated to the young god who had left them and was now striding into the river.

"LETHE!" Percy roared, making Piper jump five feet into the air. "GET YOUR BUTT DOWN HERE RIGHT NOW!"

"Percy," Piper hissed. "Don't talk to the river like that!" I raised a hand, motioning for her to be quiet for a moment. Percy knew what he was doing… at least I hoped so.

"LETHE, DON'T MAKE ME SEARCH THROUGH THE ENTIRE OF TARTARUS FOR YOUR SCRAWNY, EXTREMELY GORGEOUS FACE!"

As if on cue, the water of the Lethe began to stir, slowly at first, before picking up the pace. Looking at Piper's horror struck face, I had to stifle a laugh. She must've been thinking how Percy was about to be obliterated. Instead, the water began rising and bubbling even more vigorously. Slowly, a figure began to form, rising to her full height. Her body was lithe and graceful, with long flowing hair that shone like silver in the dim light of the Underworld. Her eyes sparkled like diamonds as she looked at Percy, her frown quickly morphing into a wide smile.

She was dressed in a simple white down, the fabric billowing in the water around her as she moved. Her skin was a pale blue colour, and she seemed to glow from within. Lethe was a truly beautiful goddess, but it was her aura that really captivated me. Despite being the goddess of forgetfulness, she radiated a powerful kind, yet sinister warth.

"Percy!" Lethe squealed before jumping into his arms, throwing him off and making him tumble in the water. "You don't write, you don't call, I thought you'd forgotten about me!" I giggled at the joke, you know, with her being the goddess of forgetfulness and all. Eventually, Percy pushed Lethe off him and got to his feet, beaming.

"Lethe, it's good to see you as well," Percy replied, his voice tingling with relief. "Glad to know you haven't forgotten me. And I'm sorry but as you know-"

"Yes, yes," she impatiently sighed, remembering Percy's motto. "Duty calls." He gave her a grin.

"Now, I would also like you to meet Nico and Piper!" She nodded, flashing me a brief smile We'd met before, back when Percy was down here after getting lost.

"OMG, what happened to Calypso!" Lethe suddenly cried, looking wide-eyed at Piper. "Did you two break up already? You were such a sweet couple." I snorted.

"Lethe," Percy sighed. "We're still together and Calypso is on Olympus, strengthening its defence." The goddess gave a slight nod, although she didn't look convinced.

"So what brings you here?" she asks, sitting down on a nearby rock. "I assume you aren't here to have a catchup." Percy gave her a wry smile.
"I need a favour from you, Lethe," he said, causing her to raise an eyebrow.

"Wow, so blunt. What happened to you in the Overworld. Last time we met, Calypso had to drag you away from me because you were so eager to talk, or was it Nico dragging you.. Eh, must've forgotten again. This time, it's 'hi and I need a favour?'"

"Honestly, as fun as talking to you is, I'm sure you've heard about the current foe of Olympus." I expected Lethe to nod, and tell Percy all about how scary he is, but no. The goddess simply frowned, shaking her head.

"No one wants to visit Lethe," she said sadly. "I don't hear the news much these days, especially with fewer and fewer people asking for rebirth."

"I wonder why," Piper whispered to me cheekily.

"Well either way, I really really need your help," Percy began, pouting. He looked at her with his big, green, adorable eyes, a look he used to get what he wanted. It had a 45% success rate, which was pretty high.

"Hmm well let me hear the favour first," she replied, curiosity getting the better of her.

"It's simple," Percy said. "I just want to talk with your mother." As if on cue, Lethe began chuckling to herself.

"Oh please, if that's what you're here for, you might as well turn around now," Lethe giggled absentmindedly. She was more focused on trying to draw a face on the dirt with her toes. Percy however wasn't talking no for an answer.

"Lethe…" he began, putting a charming smile on. "What could possibly go wrong?"

"Mother doesn't like visitors, especially unknown ones."

"Oh don't worry, I've met her before!" The goddess frowned, unsure whether he was telling the truth or not.

"Really?" she asked. "What did Mother do?"

"Eh," Percy said. "I'm pretty sure she tried to kill me, then chased me around." Lethe nodded.

"Sounds like Mother. Well in that case, you know it's not a good idea."

"Lady Lethe," Piper began, trying to hide her tremble. "Surely it wouldn't cause much harm if Percy just had a talk with her. After all, they're both immortals now, and immortals don't usually hate each other, unless you're a member of the Olympian council or have some long lasting grudge." The daughter of Aphrodite put some charmspeak into her words, and I could see the goddess slowly start to nod in agreement.

"Fair point, little girl," she eventually sighed, standing up and stretching. Then, she turned to Percy. "You better hope Mother is alone and at home. Otherwise, there's not much I can be asked to do." The lord of time shrugged, before giving a quick nod.

When Piper glared at him, he sighed, before placing a comforting hand on Lethe's shoulder.

"Thank you Lethe," he said with a grateful smile. "You're more true of a friend than most of the Olympians are to me." Lethe smiled back, but there was a hint of sadness in her eyes.

"No one ever comes and talks to me these days," she began. "Yet you Percy have no fears, and are one of the first people to strike a conversation with the very river people steer as far as possible from."

"Chances she just forgot about the people who talk to her?" I asked in a whisper to Piper who cracked a smile.

"You're kind and useful, Lethe," Percy continued. "You help people forget their painful memories and start anew. That's a valuable gift, and people should respect you rather than cowering in fear." She looked at him with surprise and gratitude, flashing him another smile. Taking one last look around, Lethe slowly grew brighter and brighter, before flashing away. I made sure to cover both mine and Piper's eyes.

"Umm Percy?" Piper began. Immediately, his head jerked up and swivelled around to face me.

"What's up?" he asked. I noticed Piper fidgeting with the hem of her shirt, something I didn't blame her for. In the Underworld, with the goddess of oblivion, next to a river that could wipe my entire memory, even I was scared, despite being a son of Hades. Honestly, most people would think that this is my home, but I was just as frightened as the daughter of Aphrodite, although I was putting on a strong face.

"Who exactly is Lady Lethe's mother?" she asked, tilting her head to the side. For a moment, Percy grew silent and was very interested in the yellow river again.

"That's a good question, who is it?" I frowned. If Lethe was the goddess of a river, wouldn't her mother be the mother of all Oceanids? If so, her mother should be Tethys and her father Oceanus? Tethys despises Percy, but she couldn't be asked to kill him, especially with him being the Lord of Time. I know for a fact Percy never met Tethys before his godhood, although I'm not sure about after. There were quite a few nights where Percy would go on long, moonlit walks by himself.

Before Percy could even answer, I heard an ear shattering feminine scream of glee, followed by Lethe's voice saying, "Oh come on Mother!" As the noise settled, I could see Lethe walking back towards us, a woman beside her who was shrouded in a cloak. I couldn't make out her features, but her presence sent a shiver down my spine. Lethe gestured towards us, and the woman lowered her hood, revealing her face.

Her hair was a dark mix of red-black, and it cascaded down her shoulders in wild curls. Her skin was pale and her eyes were dark, voids of black holes that seemed to bore into my soul. She wore a tight-fitting dress made of black leather, with silver accents that glinted in the dim light of the underworld. I couldn't put my finger on it, but there was something about her that made me uneasy. Maybe it was the way she held herself, like a predator ready to pounce. Or maybe it was the sly smirk on her lips that seemed to suggest she knew something we didn't.

Her eyes studied each and every one of us, first looking at Piper, then at me, and then Percy. She skipped past Piper quickly, and her gaze lingered on me for a little longer, but when she saw Percy, she broke into a grin. This woman's grin was not a grin that made you want to laugh, but a grin that made you want to sprint as fast as you could in the opposite direction and never look back.

All of a sudden, it clicked. Only one goddess could pull off such a creepy, sadistic smile that even Ares couldn't muster. I couldn't believe I hadn't realised it sooner. It was as if a veil had been lifted from my eyes, and I could finally see the truth. This woman was Lethe's mother, and she was powerful. More powerful than any deity I had ever encountered. I watched as she moved towards us, her steps slow and deliberate. There was something almost hypnotic about the way she walked, as if she were drawing us in with every stride. When she finally stopped in front of us, she once again inspected us over with a critical eye, as if we were her prey and she was a hunter, savouring this moment. The woman's eyes flicked towards Percy again, and she let out a low chuckle, her lips curling in a smile.

"Hello again, Perseus," Eris, the goddess of strife purred, her voice dripping with honeyed malice.

Little bit of a plot twist at the end. Got some interesting stuff for the next chapter as well, involving some Eris stuff, as well as a two other POVs (hopefully!) As always, please do review. It's always nice for me to read through reviews. Sort of fills me with determination to finish it off!