I stepped closer to the tunnel. I could barely get within fifty feet without the breath being sucked out of my lungs.

“FRANK!” I yelled. “FRANK?”

It was hopeless, I knew. There was no way Frank could have survived that. Caligula’s immortal body had disintegrated instantly. Frank couldn’t have lasted more than a few seconds longer, held together by sheer courage and force of will, just to be sure he took Caligula down with him.

I wished I could cry. I vaguely recalled having tear ducts, once upon a time.

Now all I had was despair, and the knowledge that as long as I wasn’t dead, I had to try to help my remaining friends, no matter how much I hurt.

“I’m so sorry,” I said to the flames.

The flames didn’t answer. They didn’t care who or what they destroyed.

I fixed my gaze on the crest of the hill. Hazel, Meg, and the last of the Twelfth Legion were on the other side, fighting off the undead. That’s where I needed to be.

“Okay,” I told One Eye. “I’m ready.”

Got two words for you:

Swiss Army unicorns, man!

Okay, that’s four words.

IF YOU EVER GET the chance to see weaponized unicorns in action, don’t. It’s something you can’t un-see.

As we got closer to the city, I detected signs of continuing battle: columns of smoke, flames licking the tops of buildings, screams, shouts, explosions. You know, the usual.

One Eye dropped me at the Pomerian Line. He snorted in a tone that said, Yeah, good luck with that, then galloped away. Pegasi are intelligent creatures.

I glanced at Temple Hill, hoping to see storm clouds gathering, or a divine aura of silver light bathing the hillside, or an army of my sister’s Hunters charging to the rescue. I saw nothing. I wondered if Ella and Tyson were still pacing around the shrine of Diana, checking the fire pit every thirty seconds to see if the Sibyl’s jelly-jar shards were cooked yet.

Once again, I had to be a cavalry of one. Sorry, New Rome. I jogged toward the Forum, which was where I caught my first glimpse of the unicorns. Definitely not the usual.

Meg herself led the charge. She was not riding a unicorn. No one who values their life (or their crotch) would ever dare ride one. But she did run alongside them, exhorting them to greatness as they galloped into battle. The beasts were outfitted in Kevlar with their names printed in white block letters along their ribs: MUFFIN, BUSTER, WHANGDOODLE, SHIRLEY, and HORATIO, the Five Unicorns of the Apocalypse. Their leather helmets reminded me of those worn by football players in the 1920s. The steeds’ horns were fitted with specially designed…What would you call them? Attachments? Imagine, if you will, massive conical Swiss Army knives, with various slots from which sprang a convenient variety of destructive implements.

Meg and her friends slammed into a horde of vrykolakai—former legionnaires killed in Tarquin’s previous assault, judging from their grungy bits of armor. A member of Camp Jupiter might have had trouble attacking old comrades, but Meg had no such qualms. Her swords whirled, slicing and dicing and making mounds and mounds of julienned zombies.

With a flick of their snouts, her equine friends activated their favorite accessories: a sword blade, a giant razor, a corkscrew, a fork, and a nail file. (Buster chose the nail file, which did not surprise me.) They plowed through the undead, forking them, corkscrewing them, stabbing them, and nail-filing them into oblivion.

You may wonder why I did not find it horrifying that Meg would use unicorns for war while I had found it horrifying that the emperors had used pegasi for their chariot. Setting aside the obvious difference—that the unicorns weren’t tortured or maimed—it was clear the one-horned steeds were enjoying themselves immensely. After centuries of being treated as delightful, fanciful creatures who frolicked in meadows and danced through rainbows, these unicorns finally felt seen and appreciated. Meg had recognized their natural talent for kicking undead posterior.

“Hey!” Meg grinned when she saw me, like I’d just come back from the bathroom instead of the brink of doomsday. “It’s working great. Unicorns are immune to undead scratches and bites!”

Shirley huffed, clearly pleased with herself. She showed me her corkscrew attachment as if to say, Yeah, that’s right. I ain’t your Rainbow Pony.

“The emperors?” Meg asked me.

“Dead. But…” My voice cracked.

Meg studied my face. She knew me well enough. She had been at my side in moments of tragedy.

Her expression darkened. “Okay. Grieve later. Right now, we should find Hazel. She’s”—Meg waved vaguely toward the middle of the town—“somewhere. So is Tarquin.”

Just hearing his name made my gut contort. Why, oh, why couldn’t I be a unicorn?

We ran with our Swiss Army herd up the narrow, winding streets. The battle was mostly pockets of house-to-house combat. Families had barricaded their homes. Shops were boarded up. Archers lurked in upper-story windows on the lookout for zombies. Roving bands of eurynomoi attacked any living thing they could find.

As horrible as the scene was, something about it seemed oddly subdued. Yes, Tarquin had flooded the city with undead. Every sewer grate and manhole cover was open. But he wasn’t attacking in force, sweeping systematically through the city to take control. Instead, small groups of undead were popping up everywhere at once, forcing the Romans to scramble and defend the citizenry. It felt less like an invasion and more like a diversion, as if Tarquin himself were after something specific and didn’t want to be bothered.

Something specific…like a set of Sibylline Books he’d paid good money for back in 530 BCE.

My heart pumped more cold lead. “The bookstore. Meg, the bookstore!”

She frowned, perhaps wondering why I wanted to shop for books at a time like this. Then realization dawned in her eyes. “Oh.”

She picked up speed, running so fast the unicorns had to break into a trot. How I managed to keep up, I don’t know. I suppose, at that point, my body was so far beyond help it just said, Run to death? Yeah, okay. Whatever.

The fighting intensified as we climbed the hill. We passed part of the Fourth Cohort battling a dozen slavering ghouls outside a sidewalk café. From the windows above, small children and their parents were tossing things at the eurynomoi—rocks, pots, pans, bottles—while the legionnaires jabbed their spears over the tops of their locked shields.

A few blocks farther on, we found Terminus, his World War I greatcoat peppered with shrapnel holes, his nose broken clean off his marble face. Crouching behind his pedestal was a little girl—his helper, Julia, I presumed—clutching a steak knife.

Terminus turned on us with such fury I feared he would zap us into stacks of customs declaration forms.

“Oh, it’s you,” he grumbled. “My borders have failed. I hope you’ve brought help.”

I looked at the terrified girl behind him, feral and fierce and ready to spring. I wondered who was protecting whom. “Ah…maybe?”

The old god’s face hardened a bit more, which shouldn’t have been possible for stone. “I see. Well. I’ve concentrated the last bits of my power here, around Julia. They may destroy New Rome, but they will not harm this girl!”

“Or this statue!” said Julia.