What would you do if you woke up one morning and found a satyr on your front porch, and he explained that he was going to take you to a special camp for people like you: half-god, half-human?

You might be tempted to laugh, thinking it’s a practical joke. Or maybe you’d think it was great. But if you’ve read the Percy Jackson books, you would also be seriously worried. Being a demigod may sound glamorous, but in Percy’s world, the child of a god can look forward to a life full of hardships and danger. Heroes, whether they are on a quest or just trying to live through the school year, must always stay on their toes and on the lookout for monsters.

Imagine you’re living in Percy’s world: Does that donut store on the corner make a shiver run down your spine? Does the popularity of a certain coffee chain have anything to do with the mermaid on its logo? And what about the homeless man under the bridge near your apartment: Does no one think it strange that he wears a muffler and trench coat all year round?

Or maybe you live in the country, and suddenly a lot of cattle are mysteriously disappearing. Is it a coyote problem, or a wandering monster snacking on your uncle Walt’s best milk cows? What really started those California wildfires: a careless camper or a fire-breathing chimera?

To Percy and his classmates, asking these kinds of questions could mean the difference between life and  …