The Titan's Curse

The Titan's Curse by Rick Riordan is the third book in the Percy Jackson and the Olympians series. When Percy receives an urgent call from his friend Grover, him and his two friends Annabeth and Thalia immediately come out to find him. It turns out that he had discovered two powerful new half bloods.
But that's not all that awaits them. When Annabeth goes missing, Percy and Thalia must unite with the Hunters to rescue their friend and withstand the trap the evil Titan lord has set up for them.
The first two books in the series, The Lightning Thief and The Sea of Monsters are about the adventures Percy and his friends experience, and what a true hero means. Fun, fast, and hilarious reads. This is definitely the best in the series so far.