ROBERT SIEGEL, host:

From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.

MICHELE NORRIS, host:

And I'm Michele Norris.

Goodbye, canoeing and camp songs. Hello, swordfights.

From Texas to New York, independent bookstores have been running day camps for children based on Rick Riordan's series of novels called "Percy Jackson & the Olympians." The series has sold 15 million copies.

NPR's Margot Adler joins some campers for an adventure straight out of Greek mythology.

MARGOT ADLER: Campers Georgia Silverman, Validine Bushwa(ph), Dinah Schone and Sophie Kleinborg(ph) are quick to tell me about their most exciting quest so far.

Unidentified Child #1: Jackie(ph), one of the counselors, got kidnapped.

Unidentified Child #2: Got kidnapped by Medusa.

Unidentified Child #1: And we had to slay Medusa and save Jackie.

Unidentified Child #2: And we couldn't look into Medusa's eyes.

Unidentified Child #1: So we had to, like, fight and kind of look at her feet and her shadow.

ADLER: Because if you did, you might be turned into...

Unidentified Child #1: Stone. Yeah.

Unidentified Child #2: They took the head back to camp. They showed us the snakes, but not the eyes.

ADLER: The basic story in "Percy Jackson & the Olympians" is that Percy, a kid with dyslexia and ADHD, discovers he is really the son of the sea god, Poseidon, and that dangerous monsters are after him.

He goes to Camp Half-Blood, a place where he is somewhat protected with others of his kind. He then goes on various adventures, all involving Greek mythology but mixed in with the modern world. To get to Mount Olympus, for example, you have to go to the 600th floor of the Empire State Building.

Prospect Park in Brooklyn is filled with wooded paths, groves of trees and even a few classical-looking buildings. Here, this Camp Half-Blood is protected by the Golden Fleece, which seems to be a yellow T-shirt. You give offerings to the gods before you eat. There are daily quests. A counselor found one prophecy on his cell phone.

The day I was there, one group was engaged in fighting with swords made of foam and masking tape and shields they designed.

Counselor Jason McConnell explains the rules.

Mr. JASON McCONNELL (Camp Counselor): Let's say Georgia slashes Jai's leg, he's got to go on one leg.

ADLER: If you hit the neck or the head, it's a kill.

Unidentified Woman #1: Ready.

Unidentified Child #3: (Unintelligible).

Unidentified Woman #1: Go.

(Soundbite of swordfight)

Unidentified Woman #1: Use those shields, protect your body.

ADLER: Another group of kids was creating a labyrinth with string and colored squares of paper. They hope to use it to trap monsters, but it's first used with a trivia game. You advance through the labyrinth by answering questions. And these kids aged 7 to 11 know their stuff.

Unidentified Woman #1: Ready?

Unidentified Woman #2: What is the name of the nine-headed monster that Hercules had to kill in one of his 12 labors?

Unidentified Child #4: The Hydra.

Unidentified Woman #2: I stole Apollo's cows.

Unidentified Child #5: Hermes.

Unidentified Child #6: Oh, Hermes.

ADLER: They get some of them wrong, but not many. Dinah Schone and Georgia Silverman say they've been reading D'Aulaires' "Book of Greek Mythology."

Unidentified Child #7: Everybody reads that book.

Unidentified Child #8: My mom read the book. Her mom read that book. Everybody's mom read that book.

ADLER: Camp Half-Blood is relaxed, unregimented and definitely low-tech. The kids each have a bandanna representing their parent god - orange for Athena, yellow for Apollo and so forth. They bring their own lunch. And kids can even just sit in the shade and read a book.

The camp is run by Brownstone Books in Bedford-Stuyvesant in Brooklyn, a diverse neighborhood with a large African-American population. The owner and head of the camp is Crystal Bobb-Semple.

Ms. CRYSTAL BOBB-SEMPLE (Owner, Brownstone Books): Two or three years ago, the "Percy Jackson" series just really took off for us. And the kids were so excited about it and, you know, we got the notion to try to figure out how to extend the life of these books.

ADLER: The camp costs $375, but bookstore supporters have raised scholarships for neighborhood kids.

On this day's quest, the villain is Zeus' wife Hera. The campers figure that out by discovering feathers on the trail.

Unidentified Child #9: Hera's symbol is the peacock. We think it might be Hera.

ADLER: After a long walk through wooded paths, holding their shields in a line, there is a surprise attack from the rear.

(Soundbite of screaming)

ADLER: There's running. There's screaming. There's a monster. There's not very much fighting. What is it about Greek mythology, I asked Crystal Bobb-Semple, that makes it so enduring? Part of it, she says, is that the gods have human frailties.

Ms. BOBB-SEMPLE: You know, jealousy, envy, fate, those are wonderful themes to sort of work through, and the kids find themselves, you know, acting like the gods. So I think it's our attraction to that part of ourselves.

ADLER: The kids who I asked say they like the power of the gods and their immortality.

You might think in our world filled with videogames and superheroes that the gods and heroes of ancient Greece would have less traction. How lovely that these myths and stories are still rich fodder for our fantasies.

Margot Adler, NPR News, New York. Transcript provided by NPR, Copyright NPR.