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.