Off the Italian coast, the Mediterranean Sea

An idea began tickling at the base of Percy's skull. Before he could pursue it, more dolphin warriors climbed the stairs, hauling up the rest of his friends. Jason was unconscious. Judging from the new bruises on his face, he'd tried to fight. Hazel and Piper were bound hand and foot. Piper had a gag in her mouth, so apparently, the dolphins had discovered she could charmspeak. Frank was the only one missing, though two of the dolphins had bee stings covering their faces.

Could Frank actually turn into a swarm of bees? Percy hoped so. If he was free aboard the ship somewhere, that could be an advantage, assuming Percy could figure out how to communicate with him.

"Excellent!" Chrysaor gloated. He directed his warriors to dump Jason by the crossbows. Then he examined the girls like they were Christmas presents, which made Percy grit his teeth.

"The boy is no use to me," Chrysaor said. "But we have an understanding with the witch Circe. She will buy the women—either as slaves or trainees, depending on their skill. But not you, lovely Annabeth."

Annabeth recoiled. "You are not taking me anywhere."

Percy's hand crept to his pocket. His pen had appeared back in his jeans. He only needed a moment's distraction to draw his sword. Maybe if he could take down Chrysaor quickly, his crew would panic.

He wished he knew something about Chrysaor's weaknesses. Usually, Annabeth provided him with information like that, but apparently Chrysaor didn't have any legends, so they were both in the dark.

The golden warrior tutted. "Oh, sadly, Annabeth, you will not be staying with me. I would love that. But you and your friend Percy are spoken for. A certain goddess is paying a high bounty for your capture—alive, if possible, though she didn't say you had to be unharmed."

At that moment, Piper caused the disturbance they needed. She wailed so loudly it could be heard through her gag. Then she fainted against the nearest guard, knocking him over. Hazel got the idea and crumpled to the deck, kicking her legs and thrashing like she was having a fit.

Percy drew Riptide and lashed out. The blade should have gone straight through Crhysaor's neck, but the golden warrior was unbelievably fast. He dodged and parried as the dolphin warriors backed up, guarding the other captives while giving their captain room to battle. They chattered and squeaked, egging him on, and Percy got the sinking suspicion the crew was used to this sort of entertainment. They didn't feel their leader was in any sort of danger.

Percy hadn't crossed swords with an opponent like this since . . . well, since he'd battled the war god Ares. Chrysaor was that good. Many of Percy's powers had gotten stronger over the years, but now, too late, Percy realized that swordplay wasn't one of them.

He was rusty—at least against an adversary like Chrysaor.

They battled back and forth, thrusting and parrying. Without meaning to, Percy heard the voice of Luke Castellan, his first sword-fighting mentor at Camp Half-Blood, throwing out suggestions. But it didn't help.

The golden gorgon mask was too unnerving. The warm fog, the slick deck boards, the chattering of the warriors—none of it helped. And in the corner of his eye, Percy could see one of the dolphin-men holding a knife at Annabeth's throat in case she tried anything tricky.

He feinted and thrust at Chrysaor's gut, but Chrysaor had anticipated the move. He knocked Percy's sword out of his hand again, and once more Riptide flew into the sea.

Chrysaor laughed easily. He wasn't even winded, while Percy was exhausted. He pressed the tip of his golden sword against Percy's sternum.

"A good try," said the pirate. "But now you'll be chained and transported to Gaea's minions. They are quite eager to spill your blood and wake the goddess."

Percy saw red. It felt like he kept failing with everything they faced on this quest. The sea was his domain, he was supposed to be their ace in the sleeve when sailing. And he'd let Chrysaor's ship sneak up on them, and he couldn't even defeat him with his sword.

Percy didn't think. He just launched himself at Chrysaor, grabbing him by the throat. Chrysaor's sword pushed against his stomach, but the mark of Achilles held up. Percy reached out with his will for the sea again, and this time he pushed against whatever was fighting him—probably Chrysaor's mental grip, now that Percy knew who he was—hard enough to break it. The Argo II rocked, making the dolphin-men stumble and helping Percy drive Chrysaor toward the railing.

Chrysaor kicked Percy back. He swung his sword at Percy, who caught the blade with his bare hand and forced it down. He was vibrating with anger.

Percy couldn't see Chrysaor's face, but he imagined that behind his mask, his eyes were wide. "You—you took on the Curse of Achilles?"

"You can't hurt me," Percy growled. "Leave now, while you still can."

Chrysaor only laughed. "You don't even know what kind of life you've cursed yourself with. Besides, I still have the advantage."

Annabeth cried out in pain. Percy turned and saw that her captor had pressed the knife into her throat hard enough to draw blood. More dolphin-men were holding their weapons above the rest of Percy's friends, ready to hurt them at their captain's command.

Percy met Annabeth's eyes. She stared back at him, and from the sharp glint in her eyes, he knew her injury wasn't too bad. But she was still telling him to stand down. To find another way.

Nothing like total failure to generate great ideas.

As Percy stood there, disarmed and outnumbered, the plan formed in his head. He was so used to Annabeth providing Greek legend information that he was kind of stunned to actually remember something useful, but he had to act fast. He couldn't let anything happen to his friends. He wasn't going to lose Annabeth—not again.

Percy couldn't beat Chrysaor. At least not while he had his crew behind him. But without them . . . maybe then Percy could defeat him. Or with his friends, they could overwhelm him together.

How to deal with Chrysaor's crew? Percy put the pieces together: the pirates had been turned into dolphin-men millennia ago when they had kidnapped the wrong person. Percy knew that story. Heck, the wrong person in question had threatened to turn him into a dolphin. And when Chrysaor said the crew wasn't afraid of anything, one of the dolphins had nervously corrected him. Yes, Chrysaor said. But he's not here.

Percy glanced toward the stern and spotted Frank, in human form, peeking out from behind a ballista, waiting. Percy resisted the urge to smile. The big guy claimed to be clumsy and useless, but he always seemed to be in exactly the right place when Percy needed him.

The girls . . . Frank . . . the ice chest.

It was a crazy idea. But, as usual, that was all Percy had.

"Fine!" Percy shouted, so loudly that he got everyone's attention. "Take us away, if our captain will let you."

Chrysaor turned his golden mask. "What captain? My men searched the ship. There is no one else."

Percy raised his hands dramatically. "The god appears only when he wishes. But he is our leader. He runs our camp for demigods. Doesn't he, Annabeth?"

Annabeth was quick. "Yes!" She nodded enthusiastically. "Mr. D! The great Dionysus!"

A ripple of unease passed through the dolphin-men. One dropped his word.

"Stand fast!" Chrysaor bellowed. "There is no god on this ship. They are trying to scare you."

"You should be scared!" Percy looked at the pirate crew with sympathy. "Dionysus will be severely cranky with you for having delayed our voyage. He will punish all of us. Didn't you notice the girls falling into the wine god's madness?"

Hazel and Piper had stopped the shaking fits. They were sitting on the desk, staring at Percy, but when he glared at them pointedly, they started hamming it up again, trembling and flopping around like fish. The dolphin-men fell over themselves trying to get away from their captives.

"Fakes!" Chrysaor roared. "Shut up, Percy Jackson. Your camp director is not here. He was recalled to Olympus. This is common knowledge."

"So you admit Dionysus is our director!" Percy said.

"He was," Chrysaor corrected. "Everyone knows that."

Percy gestured at the golden warrior like he'd just betrayed himself. "You see? We are doomed. If you don't believe me, let's check the ice chest!"

Percy stormed over to the magical cooler. No one tried to stop him. He knocked open the lid and rummaged through the ice. There had to be one. Please. He was rewarded with a silver-and-red can of soda. He brandished it at the dolphin warriors as if spraying them with bug repellent.

"Behold!" Percy shouted. "The god's chosen beverage. Tremble before the horror of Diet Coke!"

The dolphin-men began to panic. They were on the edge of retreat. Percy could feel it.

"The god will take your ship," Percy warned. "He will finish your transformation into dolphins, or make you insane, or transform you into insane dolphins! Your only hope is to swim away now, quickly!"

"Ridiculous!" Chrysaor's voice turned shrill. He didn't seem sure where to level his sword—at Percy or his own crew.

"Save yourselves!" Percy warned. "It is too late for us!"

Then he gasped and pointed to the spot where Frank was hiding. "Oh, no! Frank is turning into a crazy dolphin!"

Nothing happened.

"I said," Percy repeated, "Frank is turning into a crazy dolphin!"

Frank stumbled out of nowhere, making a big show of grabbing his throat. "Oh, no," he said, like he was reading from a teleprompter. "I am turning into a crazy dolphin."

He began to change, his nose elongating into a snout, his skin becoming sleek and gray. He fell to the deck as a dolphin, his tail thumping against the boards.

The pirate crew disbanded in terror, chattering and clicking as they dropped their weapons, forgot the captives, ignored Chrysaor's orders, and jumped overboard. In the confusion, Annabeth moved quickly to cut the bonds on Hazel, Piper, and Coach Hedge.

Within seconds, Chrysaor was alone and surrounded. Percy and his friends had no weapons except for Annabeth's knife and Hedge's hooves, but the murderous looks on their faces evidently convinced the golden warrior he was doomed.

He backed to the edge of the rail.

"This isn't over, Jackson," Chrysaor growled. "I will have my revenge—"

His words were cut short by Frank, who had changed form again. An eight-hundred-pound grizzly bear can definitely break up a conversation. He sideswiped Chrysaor and raked the golden mask off his helmet. Chrysaor screamed, instantly covering his face with his arms and tumbling into the water.

They ran to the rail. Chrysaor had disappeared. Percy thought about chasing him, but he didn't know these waters, and he didn't want to confront that guy alone again—no matter what protection the Curse of Achilles afforded him.

"That was brilliant!" Annabeth kissed him, which made him feel a little better.

"It was desperate," Percy corrected. "And we need to get rid of this pirate trireme."

"Burn it?" Annabeth asked.

Percy looked at the Diet Coke in his hand. "No. I've got another idea."

Getting rid of Chrysaor's ship was what did it. After opening the flood valves, filling it with Diet Coke, and summoning a massive wave to submerge it—Percy was drained. The wave wasn't even as taxing as some of the other feats he'd accomplished with his powers, but after the day's adventures, it was enough.

As soon as they couldn't see the ship anymore, Percy stumbled and slumped against the Argo II's railing.

Annabeth grabbed his arm. "Percy!"

"I'm fine," he said, standing with her help. "Just tired." At Piper, Jason, and Leo's curious looks, he added, "Side effect of the Curse of Achilles. If I'm not fighting, I'm sleeping." Percy was getting really tired of saying that. And of needing to sleep so much during such a pivotal quest.

They decided to fly the rest of the way to Rome. Jason insisted he was well enough to take sentry duty. Even though Percy didn't want to let his guard down after the surprise attack earlier, he knew he needed the break. In any case, Annabeth forced him to go anyway and threatened to make him listen to a Coach Hedge martial arts lecture if he didn't.

Once he was alone, Percy thought about what Chrysaor had said about the mark of Achilles—that he didn't know what he had cursed himself with. But after everything that happened on the journey to Alaska, Percy was starting to figure it out. For one thing, the exhaustion wasn't good for a demigod who was constantly in the middle of a perilous quest. And for another, one good hit would take him out. It didn't matter how big or small—Luke's sacrifice was evidence of that—but if an enemy figured out his weak spot, that would be it for him. In some ways, he was more vulnerable than he had ever been before bathing in the Styx.

That was what Achilles had tried to warn him about, back in the Underworld. And for the first time, Percy almost wished he had listened.