So far most of the reviewers managed to guess who was going to show up next...which isn't much, since it's only been five people. Anyway, even if you know the who, there's still the 'why'!

As you can probably guess, this story takes place during The Mark of Athena; this time, somewhere near the middle. If you've read the book recently it will probably be easy to place the events. For those who haven't, they're speeding away from America across the Pacific at the moment.

Disclaimer: I do not own Heroes of Olympus.

Leo had forgotten to turn on the sonar. How could he have been so stupid? Yeah, he'd been dropped something like twenty feet into a bunch of angry Romans who thought he'd tried to destroy their camp, but he'd completely forgotten and now they were being attacked.

Stupid!

"What's - whoa!" The voice was definitely Percy's, yelping as he noticed the monster. "Shrimpzilla!"

"I noticed!"

The monster's tentacles whipped across the deck, lashing it to the ship and knocking Percy off his feet. Dozens more of them gripped the masts, messing up the sails and the rigging.

Coach Hedge snatched his baseball bat off the deck, but Leo doubted that was going to do any good.

Jason was cutting tentacles to pieces, but more took the place of every one. Annabeth was running around with her dagger, attacking whichever part of the monster was bared to her. Frank had his bow out, sometimes shooting two arrows at a time, but it wasn't enough.

Leo looked around, frantically trying to find an answer. They needed a blast big enough to kill the monster, but it was too close to the ship to risk anything too big. What they needed was for it to let go for a second, and then Leo could just-

Something yanked the monster sharply away. It tore at the sails, leaving gashes in them and the wood of the mast, and for a minute the eight of them were frozen in surprise as something dragged the monster back underwater.

"What the hell?" Percy ran to the side of the ship, the rest of them following him.

Leo almost wished he hadn't.

Annabeth swore viciously. "Holy Hades," she ended with. "That's-"

"Freaking huge." Frank looked as nervous as Leo felt, which was slightly reassuring, because the thing that had dragged Shrimpzilla away from the boat was enormous.

All Leo could really see was its mouth, but that wasn't entirely reassuring. Considering the front teeth were as long as the Argo, he didn't want to know how big the rest of it was.

"What is that?" Jason had a death grip on his sword. He was watching in a sort of horrified fascination as the giant-ass whatever it was snapped at the shrimp creature, blood clouding the water. Leo was pretty sure it was eating the gigantic monster that had just attacked their boat.

Which, yeah, was convenient, but anything big enough to straight-up eat that thing was not something he wanted to fight.

Percy was frowning, which immediately pinged on Leo's 'something's up' radar. That, and the monster, which was now done devouring the shrimp creature from Hades, was simply sitting in the water a few feet under the surface.

Its eye slid into view, and Leo almost choked.

Forget the teeth, the eye looked like an overly-yellow, slit-pupiled sun. Or what a sun might look like up close. Leo didn't even have words to describe how big it was.

"Um," Percy said. "Guys? He's saying he's friendly."

"What?" Piper looked startled. "Since when are giant monsters friendly?"

"Since now, I guess. I don't think he's lying." Percy shrugged. "He did eat Shrimpzilla for us."

"Okay," Frank said, "But he could just have been hungry."

"He says that was part of it," Percy admitted. "But I'm usually good with sea creatures. I'm pretty sure he's not lying."

"How sure?" Annabeth asked.

"Ninety percent?"

"I say we kill it," Coach Hedge said with a maniacal gleam.

"Um," Leo interrupted, "Coach, that thing's gonna eat you faster than it did that other monster."

"He's not liking the 'kill' talk," Percy said hurriedly. "I'm pretty sure demigods have tried that before. Can we not say the k-word again?"

"I agree on not upsetting the giant sea monster," Hazel said quickly. Jason, reluctantly, nodded.

"If it's not here to fight, then what does it want?" He asked.

"Uh, he," Percy corrected Jason. "He also doesn't like being called 'it'. I think it's a sensitive subject." He looked like he was listening hard, head tilted slightly towards where the monster was lurking on their port side.

"What's he saying?" Annabeth questioned.

"He came to help," Percy murmured. "He says-" Surprise crossed his face. "We've already met his brothers?"

"What?" Percy didn't seem to her Piper's startled reply, leaning over the railing.

"Hey," he said to the giant creature, "You're not one of Loki's kids, are you?"

Annabeth made a strangled noise. "Loki? You mean-"

The eye bobbed, the creature moving in a way that Leo didn't need Percy to translate as a nod of affirmation.

"Who's Loki?" Frank asked.

"A god," Percy said. "We've run into him once before - and one of his kids. Remeber Arion's horse friend?"

"You're joking," Hazel deadpanned.

"No, he explained it to me after the Feast of Fortuna. He said he was paying back a debt, because Camp helped his dad."

"How'd we help Loki?" Hazel's brow was wrinkled. "I've never even heard of him."

"Camp Half-Blood, I mean," Percy hurried to clarify. "Before all this...we sort of, er, had a run in with him. But his kids mean well. They're just trying to do a favor for us in exchange."

"Because you helped their dad once?" Leo whistled. "Must have been a pretty big favor. What did you do?"

Percy visibly hesitated. "It's...a long story."

"Whatever, man. Anything that gets giant monsters on our side for once is a good thing in my book."

"Yeah..." Percy's eyes were distant. "It's just...the one I met before, Slepnir...he said one of his brothers had already helped us." His eyes widened, and then he turned sharply towards Piper. "You didn't meet a strangely helpful monster at any point, did you?"

Piper opened her mouth, but her eyes widened in realization before she said anything. "That wolf!" She shouted. "The one who took care of Enceladus-"

"Seriously?" Leo demanded. "He was one of this Loki guy's kids too?" Growing too much must have been a family thing. "This horse you met wasn't huge too, was he?"

"No, he was normal sized." Percy's head was tilted again. "He's saying he'll stick with us through the Atlantic, keep anything too nasty off our trail."

"That's a relief," Hazel sighed. "I could do without any more attacks. But do you mind explaining this whole 'children of Loki' thing a bit more?"

"Let's go to the dining room," Annabeth suggested. "I could do with hearing both of these stories, too."

Once Piper and Percy had both gotten done explaining their respective encounters, Hazel still looked confused.

"But how did you even meet Loki?" She pressed. "You must have done something huge. And I've never heard of him before. What's his Roman name?"

Annabeth and Percy exchanged a meaningful look. "Well," Annabeth said, "Here's the thing. Loki isn't a Greek god."

There was silence for a moment.

"That doesn't make sense," Jason said. "There's Greek and Roman. There's no other version of any of the gods."

"He's not a version of anyone," Annabeth said, slightly snappishly. "He's from a whole different pantheon. He's a Norse god, who somehow knows Hermes. That's the whole reason he ended up at camp in the first place - he was looking for Hermes."

"How many gods are there?" Frank looked astonished. "First we find out there are Greek ones still around, and now there's a whole new group of them?"

"They've been around just as long, as far as I can tell." Annabeth looked frustrated. "None of it makes any sense. The Norse have totally different creation myths, not to mention entirely different beliefs and magical creatures established in their mythology-"

"Annabeth." Percy held up a hand. "None of it makes sense. We've got a whole lot of nonsense there but on the other hand there's a giant serpent offering to keep us safe while we cross the ocean. I'd say that's pretty good."

"You didn't answer Hazel's other question," Frank pointed out. "What exactly happened?"

Percy blew out a breath. "Okay," he said eventually. "This is the part where it gets really complicated."

Okay.

Angels.

Disguised as pagan gods.

And one of this dude's absolutely enormous kids was helping guard their boat.

Leo could deal with this. Totally. But he still made Percy get in the water and shouted repair directions for the oars while he worked from the inside. There was no way he was getting in the ocean with that snake.

Admittedly, they didn't have any more trouble until they got to the mouth of the Mediterranean. The cruise ship, however annoying [and however irritating the snake apparently found its horn] wasn't it.

"Guys," Percy said, "he says he can't go any farther than this."

"What?" Leo stopped dead. "Why not?"

"The Mediterranean's Greek territory," Percy said, glancing down into the water. Leo saw the gleam of white teeth. "He can't enter it."

"I doubt that's the only reason," Annabeth said, frowning thoughtfully. "His name's Jormungandr, isn't it?"

"How'd you-"

"He's a fairly central figure in Norse mythology." Annabeth cut over Percy's question. "Legend says that's he's wrapped around the entire earth, and if he lets go...well, bad things will happen. I imagine he must have stretched himself just to follow us this far, if he's stuck like that."

"Around the entire Earth?" Piper said. "There's ice caps and stuff in the way. How's he get around that?"

"I don't know, ask him."

"I'm trying," Percy said. "Be quiet for a sec, I can't hear him answer if you're all talking." His eyes were fixed on something in the distance, head tilted. Leo wished he had some sort of communing-with-animals power. Percy made it a lot cooler than it sounded.

Percy spoke again, startling Leo out of his thoughts. "He says you're right about the wrapped-around-the-earth bit, but mostly it's-" Percy frowned. "Because he won't fit?"

"Excuse me?" Hazel's nose wrinkled in confusion.

"If he could follow us, he wouldn't me able to turn around once he got to the other end of the Mediterranean." Percy looked just as confused. "He says he's willing to offer us something that would help with the monsters, but I doubt it will be as good."

"Too big to turn around?" Leo scoffed. "Okay, maybe what we've seen of him is big, but-"

Something burst out of the water next to them. The Argo rocked in the water, destabilized by the backwash of water, and the seven demigods struggled to keep their feet. Leo felt fear thrill through him at the huge head casting a shadow over the deck. Forget its teeth, the ship was a speck next to the snake - Jormungandr's - head.

Frank swore in Latin.

"At least Coach Hedge isn't here," Hazel muttered. She'd skidded across the deck, ending up near Leo. "He'd have a stroke."

Leo couldn't find any lie in the assumption. He tensed as Jormungandr lowered his head towards the deck, letting something fall out of his mouth. Leo couldn't tell what it was. He might have said Greek fire, but the light the glass sphere gave off was red, and the stuff inside was strangely misty. He had no idea how Jormungandr had held it between his teeth without breaking it.

"What is that?" Annabeth scooted across the deck, giving only the barest glance to the giant serpent before picking it up.

"His, apparently." Percy was right behind her, giving Jormungandr more than just a passing look. The snake reared up, managing to look almost satisfied, and then plunged back into the water, sending a wave over the Argo. By the time Leo managed to pull himself back to his feet and look, there wasn't a trace of him besides the ripples in the water.

"That," Piper said, "was a lot stranger than a wolf saving my dad."

See? I said most of you were right. Of course this makes it fairly obvious who comes next, but I bet you won't guess who the fifth one is...

Read and review, please!