"A BARGAIN." LEO'S fingers twitched. "Yeah. Absolutely."

His hands went to work, and that's when Kat stepped in.

"So the thing is," said Kat, "Lord Zeus is already pissed at you, right? If you help us defeat Gaia, you could make it up to him."

Apollo wrinkled his nose. "I suppose that's possible. But it would be easier to smite you."

"You wouldn't want to end the bloodline of the best descendants you have, wouldn't you?" Kat raised her eyebrows. "I learned how to play guitar because of you. I used to always ask mama if there was ever something I could do for you when I was a kid. And Michael's been talking to me throughout our quest — you know, my namesake? For my last name, at least. He's been telling me to make this bloodline proud. To make you proud. And once I — if I take over the company and don't die tomorrow," her voice stammered around that part, but she had to play the part of the spoiled heiress, "I can work with you. For you."

Apollo gazed into the air, as if envisioning his future having her to work for him. "What do you want exactly? And what do I get out of it? Besides having my own bloodline in my favor, of course."

"First thing I need: advice." Leo talked while he did . . . whatever the fuck he was doing. "I want to know if a plan of mine will work."

He explained what he had in mind. Kat grimaced while listening to it. She hated it when he talked about this, but it was unavoidable.

The god nodded thoughtfully. "I will give you this advice for free. You might be able to defeat Gaia in the way you describe, similar to the way Ouranos was defeated aeons ago. However, any mortal close by would be utterly . . ." Apollo's voice faltered. "What is that you have made?"

Kat looked down at the contraption in Leo's hands. Layers of copper wires, like multiple sets of guitar strings, crisscrossed inside a funnel. Rows of striking pins were controlled by levers on the outside of the cone, which was fixed to a square metal base with a bunch of crank handles.

"Oh, this . . . ?" Leo glanced over at Kat, who mimed like she was plucking guitar strings, because he'd definitely seen her play guitar before.

"Um, well," said Leo, "this is quite simply the most amazing instrument ever!"

"How does it work?" asked the god.

Good question, Kat thought.

Leo turned the crank handles, Kat silently hoping the contraption wouldn't explode. A few clear tones rang out — metallic yet warm. Leo manipulated the levers and gears. Kat recognized the song that sprang forth – the same wistful melody Calypso sang on Ogygia about homesickness and longing. But, through the strings of the brass cone, the tune sounded even sadder, like a machine with a broken heart.

Leo played the song all the way through. When he was done, Kat's eyes stung. She could almost smell the fresh-baked bread from Calypso's kitchen. She could feel the water at her feet.

Apollo stared in awe at the instrument. "I must have it. What is it called? What do you want for it?"

Leo faltered, before shaking it off. "This is the Valdezinator, of course!" He puffed out his chest, which nearly made Kat snicker. "It works by, um, translating your feelings into music as you manipulate the gears. It's really meant for me, a child of Hephaestus, to use, though. I don't know if you could—"

"I am the god of music!" cried Apollo. "I can certainly master the Valdezinator. I must! It is my duty!"

"So let's wheel and deal, Music Man," said Leo. "I give you this; you give us the physician's cure."

"Oh . . ." Apollo bit his godly lip. "Well, I don't actually have the physician's cure."

"I thought you were the god of medicine."

"Yes, but I'm the god of many things! Poetry, music, the Delphic Oracle—" He broke into a sob and covered his mouth with his fist. "Sorry. I'm fine, I'm fine. As I was saying, I have many spheres of influence. Then, of course, I have the whole 'sun god' gig, which I inherited from Helios. The point is, I'm rather like a general practitioner. For the physician's cure, you would need to see a specialist — the only one who has ever successfully cured death: my son Asclepius, the god of healers."

Kat remembered talking about him with Frank, actually. Goddamn it. Of course they had to find another god.

"That's a shame, Apollo. I was hoping we could make a deal," crooned Kat.

Because Leo was so in tune with her, he turned the levers on his instrument ( Kat refused to call it a Valdezinator ), coaxing out an even sadder tune.

"Stop!" Apollo wailed. "It's too beautiful! I'll give you directions to Asclepius. He's really very close!"

"How do we know he'll help us?" asked Kat. "We've only got two days until Gaia wakes."

"He'll help!" promised Apollo. "My son is very helpful. Just plead with him in my name. You'll find him at his old temple in Epidaurus."

"What's the catch?"

"Ah . . . well, nothing. Except, of course, he's guarded."

"By what?"

"I don't know!" Apollo spread his hands helplessly. "I only know Zeus is keeping Asclepius under guard so he doesn't go running around the world resurrecting people. The first time Asclepius raised the dead . . . well, he caused quite an uproar. It's a long story. But I'm sure you can convince him to help."

"This isn't sounding like much of a deal," said Kat. "You know mama taught me better than this. What about the last ingredient — the curse of Delos. What is it?"

Apollo eyed the instrument greedily. Kat worried the god might just take it, and how could she stop him? Cortana didn't work on godly beings. And her powers weren't really suited to take down gods.

Unless she mind controlled him . . . but she can't wear herself out before the big battle. Unfortunately.

"I can give the last ingredient to you," said Apollo. "Then you'll have everything you need for Asclepius to brew the potion."

Leo played another verse. "I dunno. Trading this beautiful Valdezinator for some Delos curse—"

"It's not actually a curse! Look . . ." Apollo sprinted to the nearest patch of wildflowers and picked a yellow one from a crack between the stones. "This is the curse of Delos."

Leo stared at it. "A cursed daisy?"

Apollo sighed in exasperation. "That's just a nickname. When my mother, Leto, was ready to give birth to Artemis and me, Hera was angry, because Zeus had cheated on her again. So she went around to every single landmass on earth. She made the nature spirits in each place promise to turn my mother away so she couldn't give birth anywhere."

"Sounds like something Hera would do," commented Leo. Did he really not know the myth? So uncultured.

"I know, right? Anyway, Hera exacted promises from every land that was rooted on the earth — but not from Delos, because back then Delos was a floating island. The nature spirits of Delos welcomed my mother. She gave birth to my sister and me, and the island was so happy to be our new sacred home it covered itself in these little yellow flowers. The flowers are a blessing, because we're awesome. But they also symbolize a curse, because once we were born Delos got rooted in place and wasn't able to drift around the sea any more. That's why yellow daisies are called the curse of Delos."

"So I literally could have just picked a daisy myself and walked away," said Leo.

"No, no! Not for the potion you have in mind. The flower would have to be picked by either my sister or me. So what do you say, demigod? Directions to Asclepius and your last magical ingredient in exchange for that new musical instrument — do we have a deal?"

Leo sighed. "You drive a hard bargain, Music Man."

They made the trade.

"Excellent!" Apollo turned the levers of the instrument, which made a sound like a car engine on a cold morning. "Hmm . . . perhaps it'll take some practice, but I'll get it! Now let us find your friends. The sooner you leave, the better!"

Hazel and Frank waited at the Delos docks. Artemis was nowhere in sight.

When Kat turned to tell Apollo goodbye, the god was gone, too.

"Well, so much for patron god," muttered Kat.

"He was really anxious to practice his Valdezinator, Kitty Kat," retorted Leo. "Let a man work!"

"His what?" asked Hazel.

Leo told them about his new hobby as a genius inventor of musical funnels.

Frank scratched his head. "And in exchange you got a daisy?"

"It's the final ingredient to cure death, Zhang. It's a super daisy! How about you guys? Learn anything from Artemis?"

"Unfortunately, yes." Hazel gazed across the water, where the Argo II bobbed at anchor. "Artemis knows a lot about missile weapons. She told us Octavian has ordered some . . . surprises for Camp Half-Blood. He's used most of the legion's treasure to purchase Cyclopes-built onagers."

"Oh, no, not onagers!" said Leo. "Also, what's an onager?"

Frank scowled. "You build machines. How can you not know what an onager is? It's just the biggest, baddest catapult ever used by the Roman army."

"Fine," relented Leo. "But onager is a stupid name. They should've called them Valdezapults."

"Holy shit," Kat muttered under her breath, putting her head in one hand.

Hazel rolled her eyes. "Leo, this is serious. If Artemis is right, six of these machines will be rolling into Long Island tomorrow night. That's what Octavian has been waiting for. At dawn on August first, he'll have enough firepower to completely destroy Camp Half-Blood without a single Roman casualty. He thinks that'll make him a hero."

Frank muttered a Latin curse. "Except he's also summoned so many monstrous "allies" that the legion is completely surrounded by wild centaurs, tribes of dog-headed cynocephali, and who knows what else. As soon as the legion destroys Camp Half-Blood, the monsters will turn on Octavian and destroy the legion."

"And then Gaia rises," said Kat. "And bad shit happens."

Leo nodded. "All right . . . this just makes my plan even more important. Once we get this physician's cure, I'm going to need your help. All of you. Well, Kat already knows what I'm talking about, but."

Frank glanced nervously at the cursed yellow daisy. "What kind of help?"

Leo told Frank and Hazel his plan. The more he talked, the more shocked they looked, but when he was done neither of them told him he was crazy. A tear glistened on Hazel's cheek.

"It has to be this way," declared Leo. "Nike confirmed it. Apollo confirmed it. The others would never accept it, but Kat knows the stakes. And you guys do too; you're Romans. That's why I wanted you to come to Delos with me. You get the whole sacrifice thing — doing your duty, jumping on your sword."

Frank sniffled. "I think you mean falling on your sword."

"Whatever," Leo waved him off. "You know this has to be the answer."

"Leo . . ." Frank choked up.

Leo had tears in his eyes, but he didn't let them out. "Hey, big guy, I'm counting on you. Remember you told me about that conversation with Mars? Your dad said you'd have to step up, right? You'd have to make the call nobody else was willing to make."

"Or the war would go sideways," Frank remembered. "But still—"

"And Hazel," said Leo. "Crazy Mist-magicky Hazel, you've got to cover for me. You're the only one who can. My great-granddad Sammy saw how special you were. He blessed me when I was a baby, because I think somehow he knew you were going to come back and help me. Our whole lives, mi amiga, they've been leading up to this."

"Oh, Leo . . ." She really did burst into tears then. She grabbed him and hugged him, which was sweet until Frank started crying too and wrapped them all in his arms.

That got a little weird, but Kat loved hugs, so she didn't mind.

"Okay, well . . ." Leo gently extricated himself. "So we're in agreement?"

"I hate this plan," Frank said.

"I despise it," Hazel agreed.

"I've been telling him this since the start," Kat added.

"Think how I feel," Leo said. "But you know it's our best shot."

None of them argued.

"Let's get back to the ship," Leo looked over at the Argo II. "We have a healer god to find."