Percy, Thalia, and Nico rushed into Camp Half-Blood. To their fear, it was being attack. By birds. They weren't ordinary birds though. They were jet black all over, except for their white faces, which made it look like they were wearing masks. Percy gulped. "Uh, remember the prophecy? Beware the hidden danger within the mask." Nico scrunched up his face. "Let's not forget the next line. For nothing will be safe when it sets off for flight." Thalia pulled out her arrows and started shooting. Yet the birds were indestructible. "Why can't they die?" Annabeth raced over to them. "You're back!" "Wild goose chase." Annabeth thought for a minute. "Use the sky, sea, and ground to defeat them. Why else would they send you three off?"
Thalia, Percy, and Nico nodded. They all ran into the group. Percy drowned bird after bird. Thalia would hit the birds with lightning. Nico would raise skeleton warriors to fight or occasionally put them to sleep. Putting them to sleep just meant better targets. The other campers helped out. They would throw buckets of water at the birds, and zap them with electricity. It wasn't very powerful, but it was effective.
Soon, all but one bird was left. "Put him to sleep, Nico." Requested Thalia. Nico, who was about to fall asleep, did as she asked. Thalia grabbed the bird. "We have to see what's under their faces or masks." "How?" asked Percy. "They're indestructible." Thalia smiled. "Melt it off." Nico and Percy were both grossed-out. As were the campers. When Thalia was done, they looked down at it. "Uh? What's that!" asked Percy. Annabeth looked at it. "Hybrid of a bird and a machine. Someone's been making them. And that's the enemy you need to vanquish." Nico nodded. "Now the prophecy makes sense. We must have got it early." Percy pointed out the prophecy told them to look under the mask, so they got it in time.
Thalia, Percy, and Nico headed off again. They had to go talk to Hephaestus about the strange birds. They traveled to one of his forges. After battling off yet another monster, Nico looked up at the smoky sky. "We're here."