“Piper ended it,” he said quietly. “That was months ago, way before the Burning Maze. Now, come on. Let’s go find Caligula.”

ALAS for us and Mr. Bedrossian, there was no sign of the Cadillac Escalade on the street where we’d parked.

“We’ve been towed,” Piper announced casually, as if this was a regular occurrence for her.

She returned to the school’s front office. A few minutes later, she emerged from the front gates driving Edgarton’s green-and-gold van.

She rolled down the window. “Hey, kids. Want to go on a field trip?”

As we pulled away, Jason glanced nervously in the passenger-side rearview mirror, perhaps worried the security guard would give chase and demand we get signed permission slips before leaving campus to kill a Roman emperor. But no one followed us.

“Where to?” Piper asked when we reached the highway.

“Santa Barbara,” Jason said.

Piper frowned, as if this answer was only slightly more surprising than Uzbekistan. “Okay.”

She followed the signs for Highway 101 West.

For once, I hoped traffic would be jammed. I was not in a hurry to see Caligula. Instead, the roads were nearly empty. It was like the Southern California freeway system had heard me complaining and was now out for revenge.

Oh, go right ahead, Apollo! Highway 101 seemed to say. We estimate an easy commute to your humiliating death!

Next to me in the backseat, Meg drummed her fingers on her knees. “How much farther?”

I was only vaguely familiar with Santa Barbara. I hoped Jason would tell us it was far away—just past the North Pole, maybe. Not that I wanted to be stuck in a van with Meg that long, but at least then we could stop by Camp Jupiter and pick up a squadron of heavily armed demigods.

“About two hours,” Jason said, dashing my hopes. “Northwest, along the coast. We’re going to Stearns Wharf.”

Piper turned to him. “You’ve been there?”

“I…Yeah. Just scouting the place with Tempest.”

“Tempest?” I asked.

“His horse,” Piper said, then to Jason: “You went scouting there alone?”

“Well, Tempest is a ventus,” Jason said, ignoring Piper’s question.

Meg stopped drumming her knees. “Like those windy things Medea had?”

“Except Tempest is friendly,” Jason said. “I kind of…not tamed him, exactly, but we made friends. He’ll show up when I call, usually, and let me ride him.”

“A wind horse.” Meg pondered the idea, no doubt weighing its merits against her own demonic diaper-wearing peach baby. “I guess that’s cool.”

“Back to the question,” Piper said. “Why did you decide to scout Stearns Wharf?”

Jason looked so uncomfortable I feared he might blow out the van’s electrical systems.

“The Sibyl,” he said at last. “She told me I would find Caligula there. It’s one of the places where he stops.”

Piper tilted her head. “Where he stops?”

“His palace isn’t a palace, exactly,” Jason said. “We’re looking for a boat.”

My stomach dropped out and took the nearest exit back toward Palm Springs. “Ah,” I said.

“Ah?” Meg asked. “Ah, what?”

“Ah, that makes sense,” I said. “In ancient times, Caligula was notorious for his pleasure barges—huge floating palaces with bathhouses, theaters, rotating statues, racetracks, thousands of slaves….”

I remembered how disgusted Poseidon had been, watching Caligula tootle around the Bay of Baiae, though I think Poseidon was just jealous his palace didn’t have rotating statues.

“Anyway,” I said, “that explains why you’ve had trouble locating him. He can move from harbor to harbor at will.”

“Yeah,” Jason agreed. “When I scouted, he wasn’t there. I guess the Sibyl meant I’d find him at Stearns Wharf when I was supposed to find him. Which, I guess, is today.” He shifted in his seat, leaning as far away as possible from Piper. “Speaking of the Sibyl…there’s another detail I didn’t share with you about the prophecy.”

He told Piper the truth about the three-letter word that began with D and was not dog.

She took the news surprisingly well. She did not hit him. She didn’t raise her voice. She merely listened, then remained silent for another mile or so.

At last, she shook her head. “That’s quite a detail.”

“I should’ve told you,” Jason said.

“Um, yeah.” She twisted the steering wheel exactly the way one would break the neck of a chicken. “Still…if I’m being honest? In your position, I might’ve done the same thing. I wouldn’t want you to die either.”

Jason blinked. “Does that mean you’re not mad?”

“I’m furious.”

“Oh.”

“Furious, but also empathetic.”

“Right.”

It struck me how easily they talked together, even about difficult things, and how well they seemed to understand each other. I remembered Piper saying how frantic she’d been when she got separated from Jason in the Burning Maze—how she couldn’t bear to lose another friend.

I wondered again what was behind their breakup.

People change, Piper had said.

Full points for vagueness, girl, but I wanted the dirt.

“So,” she said. “Any other surprises? Any more tiny details you forgot?”

Jason shook his head. “I think that’s it.”

“Okay,” Piper said. “Then we go to the wharf. We find this boat. We find Caligula’s magic booties, and we kill him if we get the chance. But we don’t let each other die.”

“Or let me die,” Meg added. “Or even Apollo.”

“Thank you, Meg,” I said. “My heart is as warm as a partially thawed burrito.”

“No problem.” She picked her nose, just in case she died and never got another chance. “How do we know which is the right boat?”

“I have a feeling we’ll know,” I said. “Caligula was never subtle.”

“Assuming the boat is there this time,” Jason said.

“It’d better be,” said Piper. “Otherwise I stole this van and got you out of your afternoon physics lecture for nothing.”

“Darn,” Jason said.

They shared a guarded smile, a sort of Yes, things are still weird between us, but I don’t intend on letting you die today look.

I hoped our expedition would go as smoothly as Piper had described. I suspected our odds were better of winning the Mount Olympus Mega-God Lottery. (The most I ever got was five drachmas on a scratcher card once.)

We drove in silence along the seaside highway.

To our left, the Pacific glittered. Surfers plied the waves. Palm trees bent in the breeze. To our left, the hills were dry and brown, littered with the red flowers of heat-distressed azaleas. Try as I might, I could not help thinking of those crimson swathes as the spilled blood of dryads, fallen in battle. I remembered our cactus friends back at the Cistern, bravely and stubbornly clinging to life. I remembered Money Maker, broken and burned in the maze under Los Angeles. For their sake, I had to stop Caligula. Otherwise…No. There could be no otherwise.