I cut apart and ate the pomegranate while the three of us sat in a circle on the floor and tried to come up with a plan. Grover's nose had twitched as I started eating the seeds, so I'd held out a handful to him. He'd started to reach for them, but had stopped and pulled his hand back. He shook his head. "No, I think it's just for you. I couldn't," he said. I didn't think Persephone would mind, but if Grover wasn't willing to take the chance, neither was I.

Annabeth had gone over what she could remember of the prophecy. She claimed she might not have remembered it right, but if you've ever talked to Annabeth, you know that she's sharper than most. Her memory is pretty good. I was pretty sure she'd gotten it right. We tried to comb it for clues, but in the end the only information we could get out of it was that I was somehow prepared to do this, thanks to what I'd "shared" with Nico, and that I would have to bring him back from the Underworld. There was nothing else that we could use.

I didn't want to admit it, but I was worried. I didn't exactly have a plan. The idea had been just to waltz in there, grab Nico, and pull him out again. But the more I thought about it, the more I was sure that wasn't going to work. Hades already didn't like me. And something was wrong with Nico. It was clear that I had to get him out. But I didn't know how I was going to do it.

Of course, that wasn't about to stop me from trying. As I licked the last of the pomegranate juice off my fingers ("Ew, Percy, get a napkin!" Annabeth said, making a face), I decided that I was just going to have to wing it. I didn't care. I was going in there and I was going to get Nico back. No matter what.

I pulled my feet underneath me and stood. Annabeth and Grover looked up at me, but before they could ask what I was doing I reached over and grabbed the backpack Annabeth had brought by one of the straps. "Look, we're not going to get anything else out of the prophecy. I have to leave." It getting later; breakfast would start soon, and if I wasn't gone by then, I probably wouldn't be able to leave for another day. Chiron would want to see me, or something else would come up. I didn't want to delay my departure any more.

Annabeth frowned and snapped the laptop shut as Grover struggled to his feet. She pulled herself up using the bedspread and looked me over like she was appraising me for sale or something. Finally she sighed. "You're right. I just wish we had some kind of plan or something. I don't like the idea of you just going off without any idea of how to do this."

I shrugged. "I've done it often enough." I tried to offer her a grin. It was true, after all. Most of the time we just made things up as we went. So this time just wouldn't be any different. That wasn't so bad, was it? I looked from Annabeth to Grover. They both looked worried, but it didn't seem like they were going to try to argue me into staying. They both knew I had to go now, too.

Nico's sword was still by the door. I couldn't remember if I'd put it there last night or if I'd dropped it on the floor in my exhaustion. Maybe Annabeth had put it there. I grabbed it once more, the hilt feeling cold and firm in my hand. I swore to myself that I would see that Nico got it back. I didn't want to carry it in my hands the whole way, but thankfully with a little bit of finagling I managed to get it though my belt in a position where it wouldn't cut up my jeans or my leg.

The three of us walked down toward the beach. The other campers were just starting to stir – no one was outside their cabin yet, thank the gods, but I could hear loud voices coming from the Ares cabin and a couple of faint strains of lyre music coming from Apollo's. It wasn't hard to make it to the edge of camp unnoticed, but I knew we wouldn't have long.

Annabeth bit her lip. "Good luck, Percy." She gave me a quick hug before stepping back. Her expression was serious, but that wasn't so unusual for Annabeth.

I nodded. "I will." I glanced over at Grover, who was looking equally as serious, shifting his weight back and forth on his hooves. He tried to smile.

"Good luck," he said. "We'll keep things under control here."

"Thanks." I looked at the both of them, their faces grim in the early morning light as we stood on the beach at the edge of Camp Half-Blood. "Really, guys. Thanks." I took a deep breath. "I'll be back as soon as I can."

And I turned and walked into the waves. I knew my dad would know the second I set foot in the ocean. I could only hope he wouldn't try to stop me. Maybe, I thought, he might even try to help me. I turned and waved goodbye to Annabeth and Grover before I slid beneath the surface. They both waved back, but I could tell from the looks on their faces that they were still really worried. I promised them silently that I would be back as soon as I could. The shorter this quest, the better. I didn't much envy them, having to deal with Chiron.

Of course, I told myself, I had kept my promise. I'd still been at camp in the morning. I just hadn't stayed past morning. He'd understand when I came back with Nico.

Now, walking underwater isn't really much of a problem for me. Especially here, where the beach slid down into the ocean at a gentle slope so that the light from the surface made it pretty easy to see. I didn't even really feel cold – I mean, the water was definitely chilly against my skin, but it was kind of like being wrapped in a cold blanket. Much better than actually being wet with cold water.

I immediately turned to the south. Now that I was in the water I knew exactly where I was and exactly how to get to the Puerto Rico Trench. More specifically, I knew I was headed for Milwaukee Deep, 19°35'N, 066°30'W, 84 miles north of the coast of Puerto Rico. Suddenly my very first problem became instantly apparent. I couldn't very well walk all the way to the Puerto Rico Trench. It was much too far to reach on foot, and even if I swam it wouldn't be much faster.

I walked for at least an hour, mulling through various scenarios in my head. I'm not much of a strategist and I definitely don't tend to think things out ahead of time. That's Annabeth's strength; I'm more of a spur of the moment sort of guy. But right now it was clear that I needed a plan, and the first thing that meant was finding some kind of transportation. But it wasn't like I could magically call up a submarine or anything. I might be the son of the Sea God but that didn't mean I could do the impossible.

By now the light from the surface was a dim, murky glow above my head somewhere. I was pretty deep, off the coast of New York. I could see all right even without the light from the surface, though it was pretty creepy down here with only the mud and the sea life for company. I wasn't sure any of the local wildlife would be exactly willing to help, and the water was still too polluted for any naiads or nymphs to live here. I'd exhausted all my other options. After trying to think of various ways around it, I'd only been able to come up with one solution.

So I stopped where I was and prayed. Dad, I said silently, closing my eyes, I know you might not be proud of me right now. I guess you probably don't like the idea that I'm gay, because I wasn't really sure about it myself until just a little while ago. But Nico is important, Dad. He's important to me, and he's important to a lot of other people too. He might help us win this thing. He's on our side. I need help. Please.

Silence. A pair of blue sharks swam lazily past, not bothering to give me a second glance. I sighed, watching a few bubbles form and start their journey towards the surface. I had just about resigned myself to the fact that I really was going to have to walk all the way to Puerto Rico when I heard it.

There was a sound drifting toward me on the current. It sounded like something large was moving in my direction. I tensed, my fingers flexing and reaching into my pocket for Anaklusmos. I didn't know what could be down here or how dangerous it could be. I could only hope that the water would give me enough of a fighting advantage.

But just as quickly I became aware that I wasn't going to have to fight. Coming toward me, drawing closer with every stroke of its powerful tail, was a hippocampus – a sea horse, with the body of a white horse on top and a long, silvery fish tail on bottom.

I grinned, my racing heart immediately slowing as the hippocampus pulled up in front of me and made a sort of underwater whinnying sound. Here was my ride to the Trench. I reached out a hand and stroked the white nose. Thank you, Dad, I said silently, climbing onto the hippocampus's back and tangling my hands in its mane. He shook his head a little once and then took off toward the south with me clinging to his back.

We traveled most of the day, as near as I could figure. My orange plastic wristwatch from Wal-Mart was only rated for 165 feet and we were far deeper than that. The last time I'd tried the light nothing had happened. I guessed I would probably have to get a new one when I got back. If I got back.

I tried not to think about that. I tried to think about what it would be like to have Nico again. That thought kept me distracted enough for most of the journey, so that it didn't seem like it had been nearly long enough when the hippocampus made one of his bubbly whinnies and stopped. My underwater sense of direction told me we were close – less than five nautical miles. I couldn't see anything yet, though. The water was dark and murky and even I could feel it pressing on me like it wanted to crush me if it could only get the chance.

What is it? I tried to ask with my mind, but he either didn't want to answer me or couldn't. Something was bothering him, and that made me uneasy too. We were pretty far down – almost 28,000 feet down, in fact. We were near the deepest point in the Atlantic Ocean. It wasn't much farther to my destination, but something had the hippocampus clearly spooked.

Then I heard what could only be described as a roar. Underwater, the sound shook my bones and rumbled through my stomach like I was standing right next to a speaker with the bass turned up way too loud. The hippocampus bucked and it was all I could do to hold on and keep him from bolting. There was something down here. Something angry.

I squinted ahead into the dark water as the hippocampus swam in little agitated circles like he wanted to leave now and never come back. I was just wondering if maybe I shouldn't let him go and try to make my way past whatever had made the noise on foot when the roar sounded again. That decided the hippocampus – he bucked again, but this time I wasn't ready for it. I went sailing off his back and down to the cold sea floor, and my ride was gone in a silver flash of scales.

I picked myself up off the silt and reached into my pocket for Anaklusmos. Nico's sword still hung cold and heavy at my side, but if I was going to fight a sea creature I wanted to use my own sword. It seemed more appropriate for the job. I scanned the murky water ahead of me, trying to see what was down here. I didn't want to fight something I couldn't see. The sword's blade elongated in my hands and gave off a faint glow, lighting the water around me just a little.

Then, through the darkness, I saw two glowing eyes. They looked like a cat's eyes when you shine a light on them in the dark, big and yellow and reflective. Then I saw the mouth – a lion's mouth, lined with large yellow teeth as long as my hand. There were two massive golden paws that ended in curved claws like sickles, and a lean body covered in short fur that tapered into a golden-scaled fish tail with powerful fins. Where the mane on a normal lion would have been, this creature had a spiny frill kind of like a lionfish.

In fact, that was what this was – only literally. A leokampoi. A fish-tailed lion. And he looked hungry.

I barely had time to think anything else as the monster launched itself at me with one stroke of its tail. I ducked and rolled out of the way, trying to cut at its belly with my sword as it passed. But the leokampoi slid and rolled out of the way and turned to come at me again. It was just as agile as a real cat, only with the advantage of being near-weightless underwater.

Only most cats didn't want to eat me, I reasoned. This one definitely did, opening its mouth and letting out another rumbling roar that made my teeth rattle as it charged me again. I kicked off hard from the sand, launching myself up and over the spiny mane as it darted past. Then I twisted and kicked to angle myself down, reaching out desperately with my free hand for its tail.

Just before the tip of its fin slid beyond my reach, my fingers closed around it and suddenly I was yanked forward with a force that made it feel like my shoulder was going to come out of its socket. Well, Percy, you wanted to grab it, I thought, but that was all I had time to think before the massive tail whipped me around again and nearly into the monster's mouth. I ducked and slashed at the creature's nose, and this time the blade connected. It roared, but the terrible sound was suddenly cut off as Anaklusmos shattered the monster into a cloud of dust that exploded outward, scattering into the water and pushing me away to the sea floor with the force.

I sat there for a moment, trying to clear my head and pull myself together. That had been close. I was pretty sure that another few inches and one of those incisors would've taken off my sword arm. I had to admit, I'd hoped that my Dad might keep me safe from sea monsters during my journey. I tried not to feel hurt, but it was hard. I guessed you really couldn't expect too much when it came to the gods. Just because they did one good thing for you didn't mean they'd keep up the trend. Not even if you were their kid.

But now wasn't the time to think about that. I was close – really close. Close enough to walk the rest of the way, now that the hippocampus was long gone. So I pushed myself up off the sand and turned in the direction of the Trench to finish the journey on foot. It was hard to see where I was going this far down, even with Anaklusmos still drawn and casting a faint light ahead of me. I'd been walking for maybe an hour when I pulled up short and realized I was there.

I'd stopped just at the edge of what looked like a sheer cliff overlooking inky darkness below. There were what looked like mountains rising to the surface in the distance – Puerto Rico and the Virgin Islands. Right in front of me the sea floor dropped away, going all the way down to 28,231 feet. This was it. Milwaukee Deep, the deepest part of the Atlantic Ocean. This was an entrance to the Underworld.

Anaklusmos shrank back into pen form and I put it back in my pocket. It was as though it sensed that it wasn't right for the job ahead of me. So instead I drew Nico's sword from my belt and looked over the edge of the sea floor into the cold, crushing darkness below. For a minute I just stood there. I thought about Annabeth and Grover and their worried faces. I thought about Persephone and the pomegranate. I thought about Bianca and Chiron and even my Mom. Then I thought about Nico.

I closed my eyes, gripped Nico's sword tightly in my right hand, and jumped into Milwaukee Deep.