Back on the shore, Annabeth was talking on her cell phone but she hung up as soon as she saw me. She looked pretty shaken.
"It worked," I told her. "The rivers are safe."
"Good," she said. "Because we've got other problems. Michael Yew just called. Under the Williamsburg Bridge, there's a second army coming."
"But I just got the East River god to sink Kronos's ships!"
"It did get sunk, Percy. But there's another monster…One that survived the turnover. Michael said that it suddenly got sucked into the ocean, but after two minutes it resurfaced, and it managed to save about a dozen telkhines, three hellhounds, and about fifty dracaenae. Plus twenty or so demigods. The sea monster is an old one…very old. The one killed by your namesake."
"But I thought that was Med—Oh!"
Thousands of years ago, a hero with my namesake had killed Medusa and then a huge sea monster my dad sent as revenge to some proud queen. He killed it and took the princess as his wife. I looked at Annabeth. "And that monster hasn't reformed since he killed it? Until now?"
She nodded. "The Ethiopian Cetus. I think it's the record reformer. Like at least three thousand years. Just our luck Kronos convinced Oceanus not to send that to your father…though I doubt your dad could actually fight it, with the state of his realm."
I remembered how my father had looked like he'd aged half a century. I grimaced. "Perfect. Any good news?"
"Katie also called. She said that they'd grown a wall of poison ivy so strong it's as powerful as regular concrete. So we don't have to worry about the Brooklyn-Battery Tunnel. And they figured out something else, the Demeter cabin. They figured out how to use waterpowers. See, Demeter is the goddess of agriculture, right? And plants need sunlight, air, and water. If there are plants nearby in need, they can produce those things to help in flourish. Get it?"
"Perfect. Katie could've been one of your siblings. So about the Egyptian Seat…"
"The Ethiopian Cetus, Percy. Yes. The ancient hero used a sword of quartz to kill it. Back then it was very weak. But now it has armor of diamond, Percy. Diamond. And diamond is the hardest gemstone in existence. Celestial bronze doesn't even work on it. So how…"
She faltered. A roar shattered the silence of sleeping mortals, followed by three splashes, then another roar that rattled my eyeballs. The Ethiopian Cetus was close by. I grabbed Annabeth's hand. "The only way to fight that thing is underwater. Come on, you're coming with me."
I waded right back into the bay. Annabeth hesitated, and I rolled my eyes. "Come on, Wise Girl."
I grabbed her hand and jerked her into the bay. I made an air bubble for her to breath, and together we followed the sound of the monster roaring underwater.
