We’d killed Medea. We’d extinguished the Burning Maze. We’d freed the Erythraean Sibyl and brought relief to the mortals and withering nature spirits of Southern California.

But Caligula was still very much alive. He and his co-emperors in the Triumvirate were still intent on controlling all means of prophecy, taking over the world, and writing the future in their own sadistic image. Right now, Caligula’s fleet of evil luxury yachts was making its way toward San Francisco to attack Camp Jupiter. I could only imagine what sort of hellish destruction the emperor would rain down on Oakland and Bo’s Chicken ’N’ Waffles.

Even if we somehow managed to defeat the Triumvirate, there was still that greatest Oracle, Delphi, under the control of my old nemesis Python. How I could defeat him in my present form as a sixteen-year-old weakling, I had no idea.

But, hey. Except for that, everything was fine. The eucalyptus smelled nice.

Traffic slowed at the I-580 interchange. Apparently, California drivers didn’t follow that custom of yielding to hearses out of respect. Perhaps they figured at least one of our passengers was already dead, so we weren’t in a hurry.

Meg toyed with her window control, raising and lowering the glass. Reeee. Reeee. Reeee.

“You know how to get to Camp Jupiter?” she asked.

“Of course.”

“ ’Cause you said that about Camp Half-Blood.”

“We got there! Eventually.”

“Frozen and half-dead.”

“Look, the entrance to camp is right over there.” I waved vaguely at the Oakland Hills. “There’s a secret passage in the Caldecott Tunnel or something.”

“Or something?”

“Well, I haven’t actually ever driven to Camp Jupiter,” I admitted. “Usually I descend from the heavens in my glorious sun chariot. But I know the Caldecott Tunnel is the main entrance. There’s probably a sign. Perhaps a demigods only lane.”

Meg peered at me over the top of her glasses. “You’re the dumbest god ever.” She raised her window with a final reeee SHLOOMP!—a sound that reminded me uncomfortably of a guillotine blade.

We turned northeast onto Highway 24. The congestion eased as the hills loomed closer. The elevated lanes soared past neighborhoods of winding streets and tall conifers, white stucco houses clinging to the sides of grassy ravines.

A road sign promised CALDECOTT TUNNEL ENTRANCE, 2 MI. That should have comforted me. Soon, we’d pass through the borders of Camp Jupiter into a heavily guarded, magically camouflaged valley where an entire Roman legion could shield me from my worries, at least for a while.

Why, then, were the hairs on the back of my neck quivering like sea worms?

Something was wrong. It dawned on me that the uneasiness I’d felt since we landed might not be the distant threat of Caligula, or the old Titan base on Mount Tamalpais, but something more immediate…something malevolent, and getting closer.

I glanced in the rearview mirror. Through the back window’s gauzy curtains, I saw nothing but traffic. But then, in the polished surface of Jason’s coffin lid, I caught the reflection of movement from a dark shape outside—as if a human-size object had just flown past the hearse.

“Oh, Meg?” I tried to keep my voice even. “Do you see anything unusual behind us?”

“Unusual like what?”

THUMP.

The hearse lurched as if we’d been hitched to a trailer full of scrap metal. Above my head, two foot-shaped impressions appeared in the upholstered ceiling.

“Something just landed on the roof,” Meg deduced.

“Thank you, Sherlock McCaffrey! Can you get it off?”

“Me? How?”

That was an annoyingly fair question. Meg could turn the rings on her middle fingers into wicked gold swords, but if she summoned them in close quarters, like the interior of the hearse, she a) wouldn’t have room to wield them, and b) might end up impaling me and/or herself.

CREAK. CREAK. The footprint impressions deepened as the thing adjusted its weight like a surfer on a board. It must have been immensely heavy to sink into the metal roof.

A whimper bubbled in my throat. My hands trembled on the steering wheel. I yearned for my bow and quiver in the backseat, but I couldn’t have used them. DWSPW, driving while shooting projectile weapons, is a big no-no, kids.

“Maybe you can open the window,” I said to Meg. “Lean out and tell it to go away.”

“Um, no.” (Gods, she was stubborn.) “What if you try to shake it off?”

Before I could explain that this was a terrible idea while traveling fifty miles an hour on a highway, I heard a sound like a pop-top aluminum can opening—the crisp, pneumatic hiss of air through metal. A claw punctured the ceiling—a grimy white talon the size of a drill bit. Then another. And another. And another, until the upholstery was studded with ten pointy white spikes—just the right number for two very large hands.

“Meg?” I yelped. “Could you—?”

I don’t know how I might have finished that sentence. Protect me? Kill that thing? Check in the back to see if I have any spare undies?

I was rudely interrupted by the creature ripping open our roof like we were a birthday present.

Staring down at me through the ragged hole was a withered, ghoulish humanoid, its blue-black hide glistening like the skin of a housefly, its eyes filmy white orbs, its bared teeth dripping saliva. Around its torso fluttered a loincloth of greasy black feathers. The smell coming off it was more putrid than any dumpster—and believe me, I’d fallen into a few.

“FOOD!” it howled.

“Kill it!” I yelled at Meg.

“Swerve!” she countered.

One of the many annoying things about being incarcerated in my puny mortal body: I was Meg McCaffrey’s servant. I was bound to obey her direct commands. So when she yelled “Swerve,” I yanked the steering wheel hard to the right. The hearse handled beautifully. It careened across three lanes of traffic, barreled straight through the guardrail, and plummeted into the canyon below.

Dude, this isn’t cool

Dude just tried to eat my dude

That’s my dead dude, dude

I LIKE FLYING CARS. I prefer it when the car is actually capable of flight, however.

As the hearse achieved zero gravity, I had a few microseconds to appreciate the scenery below—a lovely little lake edged with eucalyptus trees and walking trails, and a small beach on the far shore, where a cluster of evening picnickers relaxed on blankets.

Oh, good, some small part of my brain thought. Maybe we’ll at least land in the water.

Then we dropped—not toward the lake, but toward the trees.

A sound like Luciano Pavarotti’s high C in Don Giovanni issued from my throat. My hands glued themselves to the wheel.

As we plunged into the eucalypti, the ghoul disappeared from our roof—almost as if the tree branches had purposefully swatted it away. Other branches seemed to bend around the hearse, slowing our fall, dropping us from one leafy cough-drop-scented bough to another until we hit the ground on all four wheels with a jarring thud. Too late to do any good, the air bags deployed, shoving my head against the backrest.

Yellow amoebas danced in my eyes. The taste of blood stung my throat. I clawed for the door handle, squeezed my way out between the air bag and the seat, and tumbled onto a bed of cool soft grass.