Percy Jackson and the Olympians: The Sea of Monsters. (Rick Riordan)

Life is going pretty well for Percy Jackson, considering the fact that he's a son of Poseidon, god of the sea, who is constantly being attacked by monsters. He's doing alright at school, despite the fact that he's ADHD and dyslexic, and he even has a friend named Tyson. It's the last day of school, and he's quite excited to go to camp half-blood, the only safe place for demigods. But, as luck would have it, he and Tyson are attacked by some really bad monsters, and Percy's mom doesn't think percy should go to camp half blood. Percy, Tyson, and Annabeth go there anyways, only to find tat the protective barrier is failing and the camp is constantly under attack. Also, Percy's best friend Grover is missing. The three friends depart on a quest to find the only item that can save camp half-blood,  which both Percy and Tyson are related to, and to save Grover. Meanwhile, Kronos is rising, along with an army of monsters and demigods. This is a great second book in the series, and you'll be meeting monsters and Gods left and right. This is most likely my favourite book in the series.