“I just love sitting in this room with people who understand my references,” a young Rick Riordan fan said during a sold-out author appearance at the Fox Theater in Redwood City, Calif., which housed more than 1,200 fans.

Indeed, many of the tween and teens who showed up to the October 15 event, the last stop on Riordan’s nine-day, nine-city tour are obviously deeply engrossed in his multiple ancient-myth inspired series, which include Percy Jackson and the Olympians and The Heroes of Olympus. And Publishers Weekly was there, sitting among the fans – many clad in Camp Half Blood and Camp Jupiter T-shirts – along with a member of the target audience, my 11-year-old daughter Coco, who made sure to explain some of the shirts’ more esoteric references to Riordan’s universe. For example, one girl, whose shirt was covered with colorful hand-scrawled Percy Jackson quotes, also carried a blue plastic hairbrush, a clever allusion to a mortal character who, in The Battle of the Labyrinth, throws a similar brush at the titan Kronos.

Also spotted: a large cornucopia on one of the seats (probably a horn of plenty ripped from the head of the river god Achelous, Coco explained), and a girl dressed up in Roman soldier garb (“She’s a praetor of Rome,” she told me. Duh. Obviously).

What has inspired such incredible devotion – and creativity among young fans? “Rick knows exactly what his readers want,” said Angela Mann, the youth events manager for Kepler’s Books, which hosted the event. “He writes great adventure stories that you can’t put down – and they are funny. You care about the characters right from the beginning and need to know what will happen to them. He has turned so many children into avid readers and they love him for it."

Certainly, his fans are devoted readers. As the 7 p.m. show time approached, many of the teens sat in their seats, madly flipping through Riordan’s books, including his just-released The Blood of Olympus, the fifth and final title in the Heroes of Olympus series, which hit shelves on October 7.

But when the man some fans call “Uncle Rick” took the stage, all eyes turned up front for a rapid-fire reliving of the author’s life. In less than an hour, Riordan explained how he evolved from reluctant reader (“I thought reading was kind of boring,” he admitted) to a creative middle-school teacher who often taught mythology, to, ultimately, a bestselling author who became inspired to write for young people when he saw his own son’s struggle with school.

Like any good middle-school teacher, he didn’t take himself – or really, anything– too seriously, showing silly childhood photos and some unintentionally hilarious covers of his international editions – and even presenting his first rejection letter, which he says his mother proudly framed and displayed in his family home, much to his dismay. Along the way, he also offered fans a slide of his detailed storyboarding process, and gave some words of wisdom for would-be authors in the audience: “Read a lot, write a lot, and don’t give up,” he said.

Of course, he also revved up his fans by revealing details about his next big projects: Percy Jackson’s Greek Heroes (a companion to this August’s Percy Jackson’s Greek Gods), which again will feature his popular protagonist’s own take on the famous myths, due out on August 18, 2015 – which, as fans know, just happens to be Percy’s birthday. Meanwhile, the first book in a Norse mythology series, Magnus Chase and the Gods of Asgard, is out next October. Riordan hinted to fans in Redwood City that this series will somehow connect to the Percy Jackson universe (Coco was quick to point out that this probably has something to do with the fact that Magnus’s last name is the same as that of leading lady Annabeth Chase, daughter of Athena).

Before the event, a modern-day Oracle who was selling Riordan’s books in the lobby told us to expect something of a big finish (“Just stick around until the end – that’s all I am going to tell you,” she said mysteriously). And indeed, one of the biggest squeals of the night came when Riordan announced free orange Camp Half Blood or purple Camp Jupiter shirts waiting for kids at the theater’s main doors.

“Well,” I thought, “that’s an efficient way to quickly clear a room.” We watched as Riordan’s fans filed down the rows towards the exits and out into the twilight to get their free shirts, as excited now to be heading out of the theater as they were when they swarmed in just a short while ago. But, really, it was just another example of Riordan’s understanding of his audience: he delivered a fast-paced and funny show, and then sent his fans happily off to the next adventure.