The second book in the Heroes of Olympus series:
"One cursed demigod. Two new heroes. A quest to unleash the god of death..."
Percy awakens from his long sleep with no memory save for that of his name. He makes his way to a camp for demigods, but so far nothing has caused any recollections of his past except for one - the name Annabeth.
Hazel should've died, but now she's on a dangerous journey with the fate of the world on her shoulders. She longs to escape from her new responsibilities on the horse that visits her in her dreams.
Frank is told he's descended from heroes, but he begs to differ. His clumsiness causes more harm than good, he still hasn't been claimed by a god, and he's struggling with a secret he only trusts Hazel to know.
All three of these demigods have their own parts to play in the Prophecy of Seven...
Rick Riordan - Heroes of Olympus: The Son of Neptune