Apollo, Meg, and Grover find themselves in the smoldering ruins of Palm Springs in this third installment in Riordan's popular Trials of Apollo series. Fires and drought are putting the dryads in danger, and Apollo knows that the only way to restore the rightful order is to free the oracle hidden below ground in a dangerous labyrinth. As the stakes get higher and Apollo experiences loss and sacrifice firsthand, the god loses some of his trademark braggadocio and begins to suspect his punishment sing his godly powers to walk the earth as a chubby human teen more than just a product of Zeus' short temper. Meanwhile, Meg begins to uncover some important secrets from her past. Of course, this is Riordan, so there's plenty of snarky banter and comedy mixed in among the drama. Amid the cinematic pacing and well-choreographed action scenes, Riordan squeezes in plenty of character development into the expanding cast of characters, even minor ones who don't get a lot of page space. Riordan's fans will appreciate seeing some familiar faces in this puzzle-filled installment, and a cliff-hanger ending will make them eager for the sequel.

Temporarily mortal Apollo and demigod Meg team up with Piper and Jason (from Riordan's Heroes of Olympus series) to rescue Herophile the Sibyl from a burning labyrinth under Los Angeles. Meanwhile, sorceress Medea wants to extract Apollo's godly essence to turn the emperor Caligula into a new sun god. High-stakes action and trademark humor remain, but many sacrifices lead this third entry into somber territory.