"You have your payment, I see," she said. "Excellent!"

"What?" Percy asked.

Kate scooped the three denarii out of Frank's hand. "Yes, that's fine. Right this way!"

She spun and trotted off toward the main entrance.

Percy looked at Coach Hedge and Frank. "A trap?"

"Probably," Frank said.

"She's not mortal," Hedge said, sniffing the air. "Probably some sort of goat-eating, demigod-destroying fiend from Tartarus."

"No doubt," Percy agreed.

"Awesome." Hedge grinned. "Let's go."

Kate got them past the ticket queue and into the aquarium with no problem.

"Right this way." Kate grinned at Percy. "It's a wonderful exhibit. You won't be disappointed. So rare we get VIPs."

"Uh, you mean demigods?" Frank asked.

Kate winked at him impishly and put a finger to her mouth. "So over here is the cold-water experience, with your penguins and beluga whales and whatnot. And over there...well, those are some fish, obviously."

For an aquarium worker, she didn't seem to know much or care much about the smaller fish. They passed one huge tank full of tropical species, and when Frank pointed to a particular fish and asked what it was, Kate said, "Oh, those are the yellow ones."

They passed the gift shop. Frank slowed down to check out a clearance table with clothes and toys.

"Take what you want," Kate told him.

Frank blinked. "Really?"

"Of course! You're a VIP!"

Frank hesitated. Then he stuffed some T-shirts in his backpack.

"Dude," Percy said, "what are you doing?"

"She said I could," Frank whispered. "Besides, I need more clothes. I didn't pack for a long trip!"

He added a snow globe to his stash, which didn't seem like clothing to Percy. Then Frank picked up a braided cylinder about the size of a candy bar.

He squinted at it. "What is-?"

"Chinese handcuffs," Percy said.

Frank, who was Chinese Canadian, looked offended. "How is this Chinese?"

"I don't know," Percy said. "That's just what it's called. It's like a gag gift."

"Come along, boys!" Kate called from across the hall.

"I'll show you later," Percy promised.

Frank stuffed the handcuffs in his backpack, and they kept walking.

They passed through an acrylic tunnel. Fish swam over their heads, and Percy felt irrational panic building in his throat.

This is dumb, he told himself. I've been underwater a million times. And I'm not even in the water.

The real threat was Kate, he reminded himself. Hedge had already detected that she wasn't human. Any minute she might turn into some horrible creature and attack them. Unfortunately, Percy didn't see much choice but to play along with her VIP tour until they could find the sea god Phorcys, even if they were walking deeper into a trap.

They emerged in a viewing room awash with blue light. On the other side of a glass wall was the biggest aquarium tank Percy had ever seen. Cruising in circles were dozens of huge fish, including two spotted sharks, each twice Percy's size. They were fat and slow, with open mouths and no teeth.

"Whale sharks," Coach Hedge growled. "Now we shall battle to the death!"

Kate giggled. "Silly satyr. Whale sharks are peaceful. They only eat plankton."

Percy scowled. He wondered how Kate knew the coach was a satyr. Hedge was wearing pants and specially fitted shoes over his hooves, like satyrs usually did to blend in with mortals. His baseball cap covered his horns. The more Kate giggled and acted friendly, the more Percy didn't like her; but Coach Hedge didn't seem fazed.

"Peaceful sharks?" the coach said with disgust. "What's the point of that?"

Frank read the plaque next to the tank. "The only whale sharks in captivity in the world," he mused. "That's kind of amazing."

"Yes, and these are small," Kate said. "You should see some of my other babies out in the wild."

"Your babies?" Frank asked.

Judging from the wicked glint in Kate's eyes, Percy was pretty sure he didn't want to meet Kate's babies. He decided it was time to get to the point. He didn't want to go any farther into this aquarium than he had to.

"So, Kate," he said, "we're looking for a guy...I mean a god, named Phorcys. Would you happen to know him?"

Kate snorted. "Know him? He's my brother. That's where we're going, sillies. The real exhibits are right through here."

She gestured at the far wall. The solid black surface rippled, and another tunnel appeared, leading through a luminous purple tank.

Kate strolled inside. The last thing Percy wanted to do was follow, but if Phorcys was really on the other side, and if he had information that would help their quest...Percy took a deep breath and followed his friends into the tunnel.

As soon as they entered, Coach Hedge whistled. "Now that's interesting."

Gliding above them were multicolored jellyfish the size of trash cans, each with hundreds of tentacles that looked like silky barbed wire. One jellyfish had a paralyzed ten-foot-long swordfish tangled in its grasp. The jellyfish slowly wrapped its tendrils tighter and tighter around its prey.

Kate beamed at Coach Hedge. "You see? Forget the whale sharks! And there's much more."

Kate led them into an even larger chamber, lined with more aquariums. On one wall, a glowing red sign proclaimed: DEATH IN THE DEEP SEAS! Sponsored by Monster Donut.

Percy had to read the sign twice because of his dyslexia, and then twice more to let the message sink in. "Monster Donut?"

"Oh, yes," Kate said. "One of our corporate sponsors."

Percy gulped. His last experience with Monster Donut hadn't been pleasant. It had involved acid-spitting serpent heads, much screaming, and a cannon.

In one aquarium, a dozen hippocampi-horses with the tails of fish-drifted aimlessly. Percy had seen many hippocampi in the wild. He'd even ridden a few; but he had never seen any in an aquarium. He tried to speak with them, but they just floated around, occasionally bonking against the glass. Their minds seemed addled.

"This isn't right," Percy muttered.

He turned and saw something even worse. At the bottom of a smaller tank, two Nereids-female sea spirits-sat cross-legged, facing each other, playing a game of Go Fish. They looked incredibly bored. Their long green hair floated listlessly around their faces. Their eyes were half closed.

Percy felt so angry, he could hardly breathe. He glared at Kate. "How can you keep them here?"

"I know." Kate sighed. "They aren't very interesting. We tried to teach them some tricks, but with no luck, I'm afraid. I think you'll like this tank over here much better."

Percy started to protest, but Kate had already moved on.

"Holy mother of goats!" cried Coach Hedge. "Look at these beauties!"

He was gawking at two sea serpents-thirty-foot-long monsters with glowing blue scales and jaws that could have bitten a whale shark in half. In another tank, peeking out from its cement cave, was a squid the size of an eighteen-wheeler, with a beak like a giant bolt cutter.

A third tank held a dozen humanoid creatures with sleek seal bodies, doglike faces, and human hands. They sat on the sand at the bottom of the tank, building things out of Legos, though the creatures seemed just as dazed as the Nereids.

"Are those-?" Percy struggled to form the question.

"Telkhines?" Kate said. "Yes! The only ones in captivity."

"But they fought for Kronos in the last war!" Percy said. "They're dangerous!"

Kate rolled her eyes. "Well, we couldn't call it 'Death in the Deep Seas' if these exhibits weren't dangerous. Don't worry. We keep them well sedated."

"Sedated?" Frank asked. "Is that legal?"

Kate appeared not to have heard. She kept walking, pointing out other exhibits. Percy looked back at the telkhines. One was obviously a youngster. He was trying to make a sword out of Legos, but he seemed too groggy to put the pieces together. Percy had never liked sea demons, but now he felt sorry for them.

"And these sea monsters," Kate narrated up ahead, "can grow five hundred feet long in the deep ocean. They have over a thousand teeth. And these? Their favorite food is demigod-"

"Demigod?" Frank yelped.

"But they will eat whales or small boats, too." Kate turned to Percy and blushed. "Sorry...I'm such a monster nerd! I'm sure you know all this, being the son of Poseidon, and all."

Percy's ears were ringing like alarm bells. He didn't like how much Kate knew about him. He didn't like the way she casually tossed out information about drugging captive creatures or which of her babies liked to devour demigods.

"Who are you?" he demanded. "Does Kate stand for something?"

"Kate?" She looked momentarily confused. Then she glanced at her name tag. "Oh..." She laughed. "No, it's-"

"Hello!" said a new voice, booming through the aquarium.

A small man scuttled out of the darkness. He walked sideways on bowed legs like a crab, his back hunched, his arms raised on either side like he was holding invisible plates.

He wore a wet suit that was several horrible shades of green. Glittery silver words printed down the side read: PORKY'S FOLLIES. A headset microphone was clamped over his greasy wiry hair. His eyes were milky blue, one higher than the other, and though he smiled, he didn't look friendly-more like his face was being peeled back in a wind tunnel.

"Visitors!" the man said, the word thundering through the microphone. He had a DJ's voice, deep and resonant, which did not at all match his appearance. "Welcome to Phorcys's Follies!"

He swept his arms in one direction, as if directing their attention to an explosion. Nothing happened.

"Curse it," the man grumbled. "Telkhines, that's your cue! I wave my hands, and you leap energetically in your tank, do a synchronized double spin, and land in pyramid formation. We practiced this!"

The sea demons paid him no attention.

Coach Hedge leaned toward the crab man and sniffed his glittery wet suit. "Nice outfit."

He didn't sound like he was kidding. Of course, the satyr wore gym uniforms for fun.

"Thank you!" The man beamed. "I am Phorcys."

Frank shifted his weight from foot to foot. "Why does your suit say Porky?"

Phorcys snarled. "Stupid uniform company! They can't get anything right."

Kate tapped her name tag. "I told them my name was Keto. They misspelled it as Kate. My brother...well, now he's Porky."

"I am not!" the man snapped. "I'm not even a little porky. The name doesn't work with Follies, either. What kind of show is called Porky's Follies? But you folks don't want to hear us complain. Behold, the wondrous majesty of the giant killer squid!"

He gestured dramatically toward the squid tank. This time, fireworks shot off in front of the glass right on cue, sending up geysers of golden sparkles. Music swelled from the loudspeakers. The lights brightened and revealed the wondrous majesty of an empty tank.

The squid had apparently skulked back into its cave.

"Curse it!" Phorcys yelled again. He wheeled on his sister. "Keto, training the squid was your job. Juggling, I said. Maybe a bit of flesh-rending for the finale. Is that too much to ask?"

"He's shy," Keto said defensively. "Besides, each of his tentacles has sixty-two razorlike barbs that have to be sharpened daily." She turned toward Frank. "Did you know the monstrous squid is the only beast known to eat demigods whole, armor and all, without getting indigestion? It's true!"

Frank stumbled away from her, hugging his gut as if making sure he was still in one piece.

"Keto!" Porky snapped-literally, since he clicked his fingers to his thumbs like crab claws. "You'll bore our guests with so much information. Less education, more entertainment! We've discussed this."

"But-"

"No buts! We're here to present 'Death in the Deep Seas!' Sponsored by Monster Donut!"

The last words reverberated through the room with extra echo. Lights flashed. Smoke clouds billowed from the floor, making donut-shaped rings that smelled like real donuts.

"Available at the concession stand," Phorcys advised. "But you've spent your hard-earned denarii to get the VIP tour, and so you shall! Come with me!"

"Um, hold it," Percy said.

Phorcys's smile melted in an ugly way. "Yes?"

"You're a sea god, aren't you?" Percy asked. "Son of Gaea?"