Graysen Foxx must use his extraordinary detective skills to solve the strange, mind-bending clues of the Illuminerdy—a secret society of school nerds who guard a powerful treasure.

Graysen Foxx is no stranger to the mysteries hidden in Ordinary Elementary—the bat-filled tunnels, the secret passageways, the underground chambers, and the sticky spiderwebs—and he's on the hunt for a creepy old painting that will guarantee his victory in the school's Halloween room contest. But finding and claiming the painting is only the beginning of a wild adventure filled with puzzles that will put Graysen's treasure-hunting skills to the test.

When Graysen finds a mysterious symbol on the back of a dusty spelling bee medal, the discovery spreads like creamy peanut butter, and fifth grader "Let's Make a Deal" Larry immediately offers to trade for it. But before Graysen can learn who Larry is working for, a masked second grader steals the medal.

Who wants the medal and why? Was it Graysen's nemesis, Raven? The second-grade spy network? Or the Doodler, the sixth-grade boss who blames a lost spelling bee for ruining his life?

While researching what the symbol might mean, Graysen and the twins, Maya and Jack, cross paths with a secret society of super-smart nerds and techies who call themselves the Illuminerdy. Ringing an ancient gong reveals a treasure so powerful, it could change the world of education forever. Now, Graysen and Raven must work together to outwit the secret society by uncovering a bone-rattling secret that the Illuminerdy will do anything to protect.