AFTER THEIR ENCOUNTER with Kymopo-what's-her-name, the Argo II limped through the Aegean, too damaged to fly, too slow to outrun monsters. They fought hungry sea serpents about every hour. They attracted schools of curious fish. At one point they got stuck on a rock, and Percy and Jason had to get out and push.

Over the course of three long days, Leo finally got the ship more or less back to working order just as they made port at the island of Mykonos.

Mia, Percy, and Annabeth went ashore to scout. Mia didn't really want to go, but she went anyway because Hazel told her to.

"So . . . what have you been up to?" Percy asked as they walked through the streets. It was pretty; lots of white stucco buildings with blue roofs, blue windows and blue doors. He looked like he was in heaven.

"Real smooth," Annabeth muttered under her breath.

Mia snickered for a second before sobering up. "I don't know," she shrugged. "I want to make a new coffee line, because I love coffee. I just don't know who to ask for advice because no one here drinks coffee, and the reception on the ship has been ass so I can't call Nina."

"You know I drink coffee, right?" Annabeth asked.

"Annabeth, you get Iced Americanos when we go to Starbucks, shut up," Mia snorted.

"Maybe I'd consider getting something else if you stay," Annabeth replied.

Mia let out a humorless laugh. "So that's what this is about."

"We want you to stay, Stargirl," Percy pleaded. "Why can't you?"

"I don't want to," she said simply. "And I promised Nina. I have to go home. I have to fulfill my father's legacy. And I . . . I want to do that. I want to change the world. Why can't you understand that?"

"You were gone for so long," Annabeth said. "You know that, right? I missed you. We missed you."

"I missed you too," Mia said. "But you have to understand why I want to do this. And, besides, you can find me at literally any time. You know where I'll be, if we survive this."

She spotted a gelato stand and strode toward it. "Let's get the crew gelato," she offered. "They deserve it. And so do I, after surviving Leo's nonsense about saving the ship or whatever from the brink of destruction."

And twenty minutes later, they were with the rest of the crew sitting on deck, without a storm or a monster attack to worry about for the first time in days, and ate ice cream. Well, except for Frank, who was lactose intolerant. He got an apple.

The day was hot and windy. The sea glittered with chop, but Hazel didn't look too seasick, so Mia figured she didn't have to worry about that.

"We saw these pelicans walking around town," Percy reported, wisely keeping their problems out of this conversation. "Like, just going through the shops, stopping at the bars."

Hazel frowned. "Monsters in disguise?"

"No," Annabeth said, laughing, "just regular old pelicans. They're the town mascots or something. And there's a 'Little Italy' section of town. That's why the gelato is so good."

"Europe is messed up." Leo shook his head. "First we go to Rome for Spanish steps. Then we go to Greece for Italian ice cream."

Mia silently agreed with him with a fist bump. She ate her chocolate-strawberry twist as her mind went awry. It was 30 July. Less than forty-eight hours until G-Day, when Gaia would awaken in all her shit-faced glory.

The strange thing was, the closer they got to 1 August, the more upbeat the crew acted. Or maybe upbeat wasn't the right word. They seemed to be pulling together for the final lap — aware that the next two days would make or break them. There was no point moping around when you faced imminent death. The end of the world made gelato taste a lot better.

Mia didn't feel that way, but she was motivated to get the hell out of this situation and return back to semi-normal life. Or, at least, a better life than what she'd been living before. Not that adventuring across the world with Nico was bad, but she'd missed settling down somewhere and being able to breathe.

Piper set down her ice-cream cup. "So, the island of Delos is right across the harbor. Artemis and Apollo's home turf. Who's going?"

"Me," Leo said immediately.

Everybody stared at him.

"What?" Leo demanded. "I'm diplomatic and stuff. Frank, Hazel, and Mia volunteered to back me up."

"We did?" Frank lowered his half-eaten apple. "I mean . . . sure we did."

Hazel's gold eyes flashed in the sunlight. "Leo, did you have a dream about this or something?"

"Yes," Leo blurted. "Well . . . no. Not exactly. But . . . you got to trust me on this, guys. I need to talk to Apollo and Artemis. I've got an idea I need to bounce off them."

Annabeth frowned. She looked like she might object, but Jason spoke up.

"If Leo has an idea," he said, "we need to trust him."

Leo gave Jason a smile. "Thanks, man."

Percy shrugged. "Okay. But a word of advice: when you see Apollo, don't mention haiku."

Hazel knitted her eyebrows. "Why not? Isn't he the god of poetry?"

"Just trust me."

"Got it." Leo rose to his feet. "And, guys, if they have a souvenir shop on Delos, I'm totally bringing you back some Apollo and Artemis bobbleheads!"

Apollo didn't seem to be in the mood for haiku. He wasn't selling bobbleheads, either.

Frank had turned into a giant eagle to fly to Delos. Leo hitched a ride with Hazel on Arion's back, and Mia shadow-traveled, and smirked when she was there before the rest of them. Not her fault that they all went before she could say anything.

They found the island deserted, maybe because the seas were too choppy for the tourist boats. The windswept hills were barren except for rocks, grass and wildflowers — and, of course, a bunch of crumbling temples. The rubble was probably very impressive, but, ever since Sparta, Mia had been on ancient ruins overload. She was so done with ruins. She wanted her skyscraper back. She missed it.

They walked down an avenue lined with white stone lions, the faces weathered almost featureless.

"It's eerie," Hazel said.

"You sense any ghosts?" Frank asked.

Mia shook her head. "The lack of ghosts is strange, but there's a reason for it. Back in ancient times, Delos was sacred ground. No mortal was allowed to be born here or die here. There are literally no mortal spirits on this whole island."

"Cool with me," Leo said. "Does that mean nobody's allowed to kill us here?"

"I didn't say that." Mia stopped at the summit of a low hill. "Look. Down there."

Below them, the hillside had been carved into an amphitheater. Scrubby plants sprouted between the rows of stone benches, so it looked like a concert for thorn bushes. Down at the bottom, sitting on a block of stone in the middle of the stage, the god Apollo hunched over a ukulele, plucking out a mournful tune.

He looked about seventeen, with curly blond hair and a perfect tan. He wore tattered jeans, a black T-shirt and a white linen jacket with glittering rhinestone lapels, like he was trying for an Elvis / Ramones / Beach Boys hybrid look. Younger than he had looked when Mia had seen him on Olympus after she'd been kidnapped by Atlas and forced to hold up the sky and join Kronos. Good times.

Mia didn't usually think of the ukulele as a sad instrument. ( Pathetic, sure. But not sad ) Yet the tune Apollo strummed was so melancholy it actually made her feel sad.

Sitting in the front row was a familiar young girl of about thirteen, wearing black leggings and a silver tunic, her dark hair pulled back in a ponytail. She was whittling on a long piece of wood — making a bow.

"Those are the gods?" Frank asked. "They don't look like twins."

"Well, think about it," Hazel said. "If you're a god, you can look like whatever you want. If you had a twin —"

"I'd choose to look like anything but my sibling," Frank agreed. "So what's the plan?"

"Don't shoot!" yelled Leo. He raised his arms and headed down to the stage.

"That, I guess," Mia muttered. "Never mind that I've met both of them before. Then again, they probably hate my guts, so."

Neither god looked surprised to see them.

Apollo sighed and went back to playing his ukulele.

When they got to the front row, Artemis muttered, "There you are. We were beginning to wonder."

"So you were expecting us, then," Leo said. "I can tell, because you're both so excited."

Apollo plucked a tune that sounded like the funeral version of 'Camptown Races'. "We were expecting to be found, bothered and tormented. We didn't know by whom. Can you not leave us to our misery?"

"You know they can't, brother," Artemis chided. "They require our help with their quest, even if the odds are hopeless."

"You two are full of good cheer," Leo said. "Why are you hiding out here anyway? Shouldn't you be . . . I dunno, fighting giants or something?"

Artemis's pale eyes made Mia feel like she was a deer carcass about to be gutted.

"Delos is our birthplace," said the goddess. "Here, we are unaffected by the Greek–Roman schism. Believe me, Leo Valdez, if I could, I would be with my Hunters, facing our old enemy Orion. Unfortunately, if I stepped off this island, I would become incapacitated with pain. All I can do is watch helplessly while Orion slaughters my followers. Many gave their lives to protect your friends and that accursed Athena statue."

"You mean Nico?" Mia asked, her voice teetering on the edge of anger. "Is he all right?"

"All right?" Apollo sobbed over his ukulele. "None of us are all right, girl! Gaia is rising!"

Artemis glared at Apollo. "Amelia Starfury, Hazel Levesque, your brother is still alive. He is a brave fighter, like both of you." She looked at Mia weirdly when she said that, but then she continued, "I wish I could say the same for my brother."

"You wrong me!" Apollo wailed. "I was misled by Gaia and that horrible Roman child!"

Frank cleared his throat. "Uh, Lord Apollo, you mean Octavian?"

"Do not speak his name!" Apollo strummed a minor chord. "Oh, Frank Zhang, if only you were my child. I heard your prayers, you know, all those weeks you wanted to be claimed. But alas! Mars gets all the good ones. I get . . . that creature as my descendant. He filled my head with compliments. He told me of the great temples he would build in my honor."

Artemis snorted. "You are easily flattered, brother."

"Because I have so many amazing qualities to praise! Octavian said he wanted to make the Romans strong again. I said fine! I gave him my blessing."

"As I recall," said Artemis, "he also promised to make you the most important god of the legion, above even Zeus."

"Well, who was I to argue with an offer like that? Does Zeus have a perfect tan? Can he play the ukulele? I think not! But I never thought Octavian would start a war! Gaia must have been clouding my thoughts, whispering in my ear."

"So fix it," Leo said. "Tell Octavian to stand down. Or, you know, shoot him with one of your arrows. That would be fine, too."

"I cannot!" Apollo wailed. "Look!"

His ukulele turned into a bow. He aimed at the sky and shot. The golden arrow sailed about two hundred feet, then disintegrated into smoke.

"To shoot my bow, I would have to step off Delos," Apollo cried. "Then I would be incapacitated, or Zeus would strike me down. Father never liked me. He hasn't trusted me for millennia!"

"Well," Artemis said, "to be fair, there was that time you conspired with Hera to overthrow him."

"That was a misunderstanding!"

"And you killed some of Zeus's Cyclopes."

"I had a good reason for that! At any rate, now Zeus blames me for everything — Octavian's schemes, the fall of Delphi —"

"Wait." Hazel made a time-out sign. "The fall of Delphi?"

Apollo's bow turned back into a ukulele. He plucked a dramatic chord. "When the schism began between Greek and Roman, while I struggled with confusion, Gaia took advantage! She raised my old enemy Python, the great serpent, to repossess the Delphic Oracle. That horrible creature is now coiled in the ancient caverns, blocking the magic of prophecy. I am stuck here, so I can't even fight him."

"Bummer," Leo said sarcastically. Mia hid her snickers with a cough.

"Bummer indeed!" Apollo sighed. "Zeus was already angry with me for appointing that new girl, Rachel Dare, as my Oracle. Zeus seems to think I hastened the war with Gaia by doing so, since Rachel issued the Prophecy of Eight as soon as I blessed her. But prophecy doesn't work that way! Father just needed someone to blame. So of course he picked the handsomest, most talented, hopelessly awesome god."

Artemis made a gagging gesture. Mia agreed with her.

"Oh, stop it, sister!" Apollo said. "You're in trouble, too!"

"Only because I stayed in touch with my Hunters against Zeus's wishes," Artemis said. "But I can always charm Father into forgiving me. He's never been able to stay mad at me. It's you I'm worried about."

"I'm worried about me, too!" Apollo agreed. "We have to do something. We can't kill Octavian. Hmm. Perhaps we should kill these demigods."

"Whoa there, Music Man." Leo threw up his hands in surrender. "We're on your side, remember? Why would you kill us?"

"It might make me feel better!" Apollo said. "I have to do something!"

"Or," Leo said quickly, "you could help us. See, we've got this plan . . ."

He told them how Hera ( ugh ) had directed them to Delos, and how Nike had described the ingredients for the physician's cure.

"The physician's cure?" Apollo stood and smashed his ukulele on the stones. "That's your plan?"

Leo raised his hands higher. "Hey, um, usually I'm all for smashing ukuleles, but—"

"I cannot help you!" Apollo cried. "If I told you the secret of the physician's cure, Zeus would never forgive me!"

"You're already in trouble," Mia pointed out. "How could it get worse?"

Apollo glared at her. "If you knew what my father is capable of, mortal, you would not ask. It would be simpler if I just smote you all. That might please Zeus —"

"Brother . . ." Artemis said.

The twins locked eyes and had a silent argument. Apparently Artemis won. Apollo heaved a sigh and kicked his broken ukulele across the stage.

Artemis rose. "Hazel Levesque, Frank Zhang, come with me. There are things you should know about the Twelfth Legion. As for you, Leo Valdez—" The goddess turned to him. "Apollo will hear you and Amelia Starfury out. See if you can strike a deal. My brother always likes a good bargain."

Frank and Hazel both glanced at Leo and Mia, like Please don't die. Then they followed Artemis up the steps of the amphitheatre and over the crest of the hill.

"Well, Leo Valdez?" Apollo folded his arms. His eyes glowed with golden light. "Let us bargain, then. What can you offer that would convince me to help you rather than kill you?"