Titan's Curse-Riordan

This is the third book of Percy Jackson and the Olympians series. The stirring of monsters has begun. Monsters not seen for thousands of years threaten to unleash death and destruction on an unprecedented scale and destroy Olympus, and it's up to Percy Jackson and his friends Grover, Annabeth and Thalia to stop them, though Percy is embarrassed to have to depend on his mother to drive him to his battles. Percy, Annabeth and Thalia are demigods, Grover is a satyr and their quest is to find the missing Artemis and the monster she was hunting. Riordan's sense of humor and and use of pop culture makes this series a hit!