I would recommend Percy Jackson and The Olympians series. If you've seen the movie, than you've got an idea of what the story is all about. But even so, the novel is a whole LOT better than the movie.
The series is completed and have an on going sequel by the name of Heroes of Olympus, which began in a new character's (also demigod) POV. Here's the summary:
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Jason has a problem. He doesn’t remember anything before waking up on a school bus holding hands with a girl. Apparently she’s his girlfriend Piper, his best friend is a kid named Leo, and they’re all students in the Wilderness School, a boarding school for “bad kids.” What he did to end up here, Jason has no idea—except that everything seems very wrong.
Piper has a secret. Her father has been missing for three days, and her vivid nightmares reveal that he’s in terrible danger. Now her boyfriend doesn’t recognize her, and when a freak storm and strange creatures attack during a school field trip, she, Jason, and Leo are whisked away to someplace called Camp Half-Blood. What is going on?
Leo has a way with tools. His new cabin at Camp Half-Blood is filled with them. Seriously, the place beats Wilderness School hands down, with its weapons training, monsters, and fine-looking girls. What’s troubling is the curse everyone keeps talking about, and that a camper’s gone missing. Weirdest of all, his bunkmates insist they are all—including Leo—related to a god.
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Basically all the books that Riordan has ever written. Hope that helps!