"The Trials of Apollo" is a fantasy book series by Rick Riordan that follows the story of Apollo, the Greek god of music and prophecy, who is transformed into a mortal teenager named Lester Papadopoulos. Stripped of his divine powers, Apollo embarks on a quest to regain his place on Mount Olympus, facing various challenges and enemies along the way. Throughout the series, Apollo teams up with demigods, including Meg McCaffrey and Leo Valdez, as they confront threats from ancient monsters and new villains. The narrative blends humor, adventure, and mythology, exploring themes of redemption and friendship in a modern setting.