He gave me a skeletal smile. “The Sea of Monsters, of course.”

I stuffed my few belongings that had survived the Hydra into a sailor’s canvas knapsack and slung it over my shoulder. I had a sneaking suspicion that one way or another I would not be spending another night aboard the CSS Birmingham.

I was on my way upstairs when something made me freeze. A presence nearby—something familiar and unpleasant. For no particular reason, I felt like picking a fight. I wanted to punch a dead Confederate. The last time I’d felt like that kind of anger …

Instead of going up, I crept to the edge of the ventilation grate and peered down into the boiler deck.

Clarisse was standing right below me, talking to an image that shimmered in the steam from the boilers—a muscular man in black leather biker clothes, with a military haircut, red-tinted sunglasses, and a knife strapped to his side.

My fists clenched. It was my least favorite Olympian: Ares, the god of war.

“I don’t want excuses, little girl!” he growled.

“Y-yes, father,” Clarisse mumbled.

“You don’t want to see me mad, do you?”

“No, father.”

“No, father,” Ares mimicked. “You’re pathetic. I should’ve let one of my sons take this quest.”

“I’ll succeed!” Clarisse promised, her voice trembling. “I’ll make you proud.”

“You’d better,” he warned. “You asked me for this quest, girl. If you let that slimeball Jackson kid steal it from you—”

“But the Oracle said—”

“I DON’T CARE WHAT IT SAID!” Ares bellowed with such force that his image shimmered.

“You will succeed. And if you don’t …”

He raised his fist. Even though he was only a figure in the steam, Clarisse flinched.

“Do we understand each other?” Ares growled.

The alarm bells rang again. I heard voices coming toward me, officers yelling orders to ready the cannons.

I crept back from the ventilation grate and made my way upstairs to join Annabeth and Tyson on the spar deck.

“What’s wrong?” Annabeth asked me. “Another dream?”

I nodded, but I didn’t say anything. I didn’t know what to think about what I’d seen downstairs. It bothered me almost as much as the dream about Grover.

Clarisse came up the stairs right after me. I tried not to look at her.

She grabbed a pair of binoculars from a zombie officer and peered toward the horizon. “At last. Captain, full steam ahead!”

I looked in the same direction as she was, but I couldn’t see much. The sky was overcast.

The air was hazy and humid, like steam from an iron. If I squinted real hard, I could just make out a couple of dark fuzzy splotches in the distance.

My nautical senses told me we were somewhere off the coast of northern Florida, so we’d come a long way overnight, farther than any mortal ship should’ve been able to travel.

The engine groaned as we increased speed.

Tyson muttered nervously, “Too much strain on the pistons. Not meant for deep water.”

I wasn’t sure how he knew that, but it made me nervous.

After a few more minutes, the dark splotches ahead of us came into focus. To the north, a huge mass of rock rose out of the sea—an island with cliffs at least a hundred feet tall. About half a mile south of that, the other patch of darkness was a storm brewing. The sky and sea boiled together in a roaring mass.

“Hurricane?” Annabeth asked.

“No,” Clarisse said. “Charybdis.”

Annabeth paled. “Are you crazy?”

“Only way into the Sea of Monsters. Straight between Charybdis and her sister Scylla.”

Clarisse pointed to the top of the cliffs, and I got the feeling something lived up there that I did not want to meet.

“What do you mean the only way?” I asked. “The sea is wide open! Just sail around them.”

Clarisse rolled her eyes. “Don’t you know anything? If I tried to sail around them, they would just appear in my path again. If you want to get into the Sea of Monsters, you have to sail through them.”

“What about the Clashing Rocks?” Annabeth said. “That’s another gateway. Jason used it.”

“I can’t blow apart rocks with my cannons,” Clarisse said. “Monsters, on the other hand …”

“You are crazy,” Annabeth decided.

“Watch and learn, Wise Girl.” Clarisse turned to the captain. “Set course for Charybdis!”

“Aye, m’lady.”

The engine groaned, the iron plating rattled, and the ship began to pick up speed.

“Clarisse,” I said, “Charybdis sucks up the sea. Isn’t that the story?”

“And spits it back out again, yeah.”

“What about Scylla?”

“She lives in a cave, up on those cliffs. If we get too close, her snaky heads will come down and start plucking sailors off the ship.”

“Choose Scylla then,” I said. “Everybody goes below deck and we chug right past.”

“No!” Clarisse insisted. “If Scylla doesn’t get her easy meat, she might pick up the whole ship. Besides, she’s too high to make a good target. My cannons can’t shoot straight up. Charybdis just sits there at the center of her whirlwind. We’re going to steam straight toward her, train our guns on her, and blow her to Tartarus!”

She said it with such relish I almost wanted to believe her.

The engine hummed. The boilers were heating up so much I could feel the deck getting warm beneath my feet. The smokestacks billowed. The red Ares flag whipped in the wind.

As we got closer to the monsters, the sound of Charybdis got louder and louder—a horrible wet roar like the galaxy’s biggest toilet being flushed. Every time Charybdis inhaled, the ship shuddered and lurched forward. Every time she exhaled, we rose in the water and were buffeted by ten-foot waves.

I tried to time the whirlpool. As near as I could figure, it took Charybdis about three minutes to suck up and destroy everything within a half-mile radius. To avoid her, we would have to skirt right next to Scylla’s cliffs. And as bad as Scylla might be, those cliffs were looking awfully good to me.

Undead sailors calmly went about their business on the spar deck. I guess they’d fought a losing cause before, so this didn’t bother them. Or maybe they didn’t care about getting destroyed because they were already deceased. Neither thought made me feel any better.

Annabeth stood next to me, gripping the rail. “You still have your thermos full of wind?”

I nodded. “But it’s too dangerous to use with a whirlpool like that. More wind might just make things worse.”

“What about controlling the water?” she asked. “You’re Poseidon’s son. You’ve done it before.”

She was right. I closed my eyes and tried to calm the sea, but I couldn’t concentrate.

Charybdis was too loud and powerful. The waves wouldn’t respond.

“I—I can’t,” I said miserably.

“We need a backup plan,” Annabeth said. “This isn’t going to work.”

“Annabeth is right,” Tyson said. “Engine’s no good.”

“What do you mean?” she asked.

“Pressure. Pistons need fixing.”

Before he could explain, the cosmic toilet flushed with a mighty roaaar! The ship lurched forward and I was thrown to the deck. We were in the whirlpool.

“Full reverse!” Clarisse screamed above the noise. The sea churned around us, waves crashing over the deck. The iron plating was now so hot it steamed. “Get us within firing range! Make ready starboard cannons!”

Dead Confederates rushed back and forth. The propeller grinded into reverse, trying to slow the ship, but we kept sliding toward the center of the vortex.

A zombie sailor burst out of the hold and ran to Clarisse. His gray uniform was smoking. His beard was on fire. “Boiler room overheating, ma’am! She’s going to blow!”

“Well, get down there and fix it!”

“Can’t!” the sailor yelled. “We’re vaporizing in the heat.”

Clarisse pounded the side of the casemate. “All I need is a few more minutes! Just enough to get in range!”

“We’re going in too fast,” the captain said grimly. “Prepare yourself for death.”

“No!” Tyson bellowed. “I can fix it.”

Clarisse looked at him incredulously. “You?”

“He’s a Cyclops,” Annabeth said. “He’s immune to fire. And he knows mechanics.”

“Go!” yelled Clarisse.

“Tyson, no!” I grabbed his arm. “It’s too dangerous!”

He patted my hand. “Only way, brother.” His expression was determined—confident, even.

I’d never seen him look like this before. “I will fix it. Be right back.”

As I watched him follow the smoldering sailor down the hatch, I had a terrible feeling. I wanted to run after him, but the ship lurched again—and then I saw Charybdis.

She appeared only a few hundred yards away, through a swirl of mist and smoke and water.

The first thing I noticed was the reef—a black crag of coral with a fig tree clinging to the top, an oddly peaceful thing in the middle of a maelstrom. All around it, water curved into a funnel, like light around a black hole. Then I saw the horrible thing anchored to the reef just below the waterline—an enormous mouth with slimy lips and mossy teeth the size of rowboats. And worse, the teeth had braces, bands of corroded scummy metal with pieces of fish and driftwood and floating garbage stuck between them.

Charybdis was an orthodontist’s nightmare. She was nothing but a huge black maw with bad teeth alignment and a serious overbite, and she’d done nothing for centuries but eat without brushing after meals. As I watched, the entire sea around her was sucked into the void—sharks, schools of fish, a giant squid. And I realized that in a few seconds, the CSS Birmingham would be next.

“Lady Clarisse,” the captain shouted. “Starboard and forward guns are in range!”

“Fire!” Clarisse ordered.

Three rounds were blasted into the monster’s maw. One blew off the edge of an incisor.

Another disappeared into her gullet. The third hit one of Charybdis’s retaining bands and shot back at us, snapping the Ares flag off its pole.

“Again!” Clarisse ordered. The gunners reloaded, but I knew it was hopeless. We would have to pound the monster a hundred more times to do any real damage, and we didn’t have that long. We were being sucked in too fast.

Then the vibrations in the deck changed. The hum of the engine got stronger and steadier.

The ship shuddered and we started pulling away from the mouth.

“Tyson did it!” Annabeth said.

“Wait!” Clarisse said. “We need to stay close!”

“We’ll die!” I said. “We have to move away.”

I gripped the rail as the ship fought against the suction. The broken Ares flag raced past us and lodged in Charybdis’s braces. We weren’t making much progress, but at least we were holding our own. Tyson had somehow given us just enough juice to keep the ship from being sucked in.