The Mark of Athena

invading Greek army. Maybe she hadn’t stayed sane.

By the time the sun rose, none of them had slept. Percy had scoured the seafloor and found nothing. The Argo II was no longer in danger of sinking, though without Leo, they couldn’t do full repairs. The ship was capable of sailing, but no one suggested leaving the area—not without their missing friends.

Piper and Annabeth sent a dream vision to Camp Half-Blood, warning Chiron of what had happened with the Romans at Fort Sumter. Annabeth explained her exchange of words with Reyna. Piper relayed the vision from her knife about the SUVs racing north. The kindly centaur’s face seemed to age thirty years during the course of their conversation, but he assured them he would see to the defenses of the camp. Tyson, Mrs. O’Leary, and Ella had arrived safely. If necessary, Tyson could summon an army of Cyclopes to the camp’s defense, and Ella and Rachel Dare were already comparing prophecies, trying to learn more about what the future held. The job of the seven demigods aboard the Argo II, Chiron reminded them, was to finish the quest and come back safely.

After the Iris-message, the demigods paced the deck in silence, staring at the water and hoping for a miracle.

When it finally came—three giant pink bubbles bursting at the surface off the starboard bow and ejecting Frank, Hazel, and Leo—Piper went a little crazy. She cried out with relief and dove straight into the water.

What was she thinking? She didn’t take a rope or a life vest or anything. But at the moment, she was just so happy that she paddled over to Leo and kissed him on the cheek, which kind of surprised him.

“Miss me?” Leo laughed.

Piper was suddenly furious. “Where were you? How are you guys alive?”

“Long story,” he said. A picnic basket bobbed to the surface next to him. “Want a brownie?”

Once they got on board and changed into dry clothes (poor Frank had to borrow a pair of too-small pants from Jason) the crew all gathered on the quarterdeck for a celebratory breakfast—except for Coach Hedge, who grumbled that the atmosphere was getting too cuddly for his tastes and went below to hammer out some dents in the hull. While Leo fussed over his helm controls, Hazel and Frank related the story of the fish-centaurs and their training camp.

“Incredible,” Jason said. “These are really good brownies.”

“That’s your only comment?” Piper demanded.

He looked surprised. “What? I heard the story. Fish-centaurs. Merpeople. Letter of intro to the Tiber River god. Got it. But these brownies—”

“I know,” Frank said, his mouth full. “Try them with Esther’s peach preserves.”

“That,” Hazel said, “is incredibly disgusting.”

“Pass me the jar, man,” Jason said.

Hazel and Piper exchanged a look of total exasperation. Boys.

Percy, for his part, wanted to hear every detail about the aquatic camp. He kept coming back to one point: “They didn’t want to meet me?”

“It wasn’t that,” Hazel said. “Just…undersea politics, I guess. The merpeople are territorial. The good news is they’re taking care of that aquarium in Atlanta. And they’ll help protect the Argo II as we cross the Atlantic.”

Percy nodded absently. “But they didn’t want to meet me?”

Annabeth swatted his arm. “Come on, Seaweed Brain! We’ve got other things to worry about.”

“She’s right,” Hazel said. “After today, Nico has less than two days. The fish-centaurs said we have to rescue him. He’s essential to the quest somehow.”

She looked around defensively, as if waiting for someone to argue. No one did. Piper tried to imagine what Nico di Angelo was feeling, stuck in a jar with only two pomegranate seeds left to sustain him, and no idea whether he would be rescued. It made Piper anxious to reach Rome, even though she had a horrible feeling she was sailing toward her own sort of prison—a dark room filled with water.

“Nico must have information about the Doors of Death,” Piper said. “We’ll save him, Hazel. We can make it in time. Right, Leo?”

“What?” Leo tore his eyes away from the controls. “Oh, yeah. We should reach the Mediterranean tomorrow morning. Then spend the rest of that day sailing to Rome, or flying, if I can get the stabilizer fixed by then.…”

Jason suddenly looked as though his brownie with peach preserves didn’t taste so good. “Which will put us in Rome on the last possible day for Nico. Twenty-four hours to find him—at most.”

Percy crossed his legs. “And that’s only part of the problem. There’s the Mark of Athena, too.”

Annabeth didn’t seem happy with the change of topic. She rested her hand on her backpack, which, since they’d left Charleston, she always seemed to have with her.

She opened the bag and brought out a thin bronze disk the diameter of a donut. “This is the map that I found at Fort Sumter. It’s…”

She stopped abruptly, staring at the smooth bronze surface. “It’s blank!”

Percy took it and examined both sides. “It wasn’t like this earlier?”

“No! I was looking at it in my cabin and…” Annabeth muttered under her breath. “It must be like the Mark of Athena. I can only see it when I’m alone. It won’t show itself to other demigods.”

Frank scooted back like the disk might explode. He had an orange-juice mustache and a brownie-crumb beard that made Piper want to hand him a napkin.