The Dark Prophecy (2017) is the second volume in Rick Riordan’s The Trials of Apollo, a five-book fantasy series for young readers. Inspired by Greek and Roman mythology and history, The Trials of Apollo follows the fallen god Apollo on his adventure-quest to find hidden oracles and save the world from a trio of cruel Roman emperors. The Trials of Apollo series takes place in the same universe as Riordan’s popular Percy Jackson books. Praised for its humor, witty dialogue, and pacing, The Dark Prophecy became a New York Times bestseller within a week of its release and has been translated into seven languages from the original English.

Events in the book occur six weeks from where The Hidden Oracle, the first of The Trials of Apollo series (see SuperSummary’s study guide for The Hidden Oracle) ended. Apollo lands in Indianapolis to find a dark and dangerous oracle, which will give him crucial guidance for his quest. He now has to reunite with his friend Meg McCaffrey, undertake a perilous journey, and, with the help of his friends, save the city from the fickle tyrant Commodus.

Before becoming a full-time writer, Riordan taught Greek mythology at the middle-school level for several years. Riordan’s writing often places elements from various mythologies in a contemporary context. This guide follows the 2018 Puffin Books UK edition.

Plot Summary

Apollo, the Greek God of light, music, healing, truth, and prophecy, has been turned into a mortal teenager called Lester Papadopoulos by his father, Zeus. In the first book of the series, Apollo met the demigod Meg McCaffrey, a 13-year-old girl, who became his “master” after she learned Apollo must serve someone to regain his godhood. To become immortal again, Apollo must consult the oracles, the chief sources of wisdom and future-telling in the series’ universe. Since the main oracles are under the control of three evil emperors from ancient Rome, Apollo and Meg go on a quest to find hidden sources of prophecy. By the end of the first book in the series, Apollo has received a prophecy from the Oracle of the Grove of Dodona but has been separated from Meg.

The prophecy of Dodona guides Apollo and his friends Leo and Calypso to Indiana. In Indianapolis, the three are attacked by blemmyae, monsters under the control of Commodus, the second of the trio of Roman emperors. Apollo and the others are rescued by Emmie and Josephine, two former Hunters of Artemis, who run a safe house called the Waystation. Commodus is preparing to take over Indianapolis and is collecting demigods and magical creatures for a “savage” games event he will hold in celebration. He has kidnapped a pair of griffins who were Emmie and Josephine’s guests at the Waystation. Emmie and Josephine’s seven-year-old adopted daughter, Georgina, went to consult the nearby oracle for advice on finding the griffins, had a mental health crisis, and was kidnapped by Commodus. The oracle is the same that Apollo is seeking, the dangerous Oracle of Trophonius. Prophecies from Trophonius can only be interpreted with a magical artifact called the Throne of Memory, which Commodus also has stolen and hoarded in his palace.

Apollo and Calypso go to the Indianapolis Zoo to rescue the kidnapped griffins from the soldiers of Commodus. Meg arrives on the spot to help them out. Meg left Apollo at the end of The Hidden Oracle to be with her stepfather Nero, one of the Triumvirate. Nero has assigned her to kill Apollo, but she escaped his guards to join Apollo again. Apollo, Leo, and Meg infiltrate the palace of Commodus, free Georgina and the other prisoners, and rescue the Throne of Memory. During a detour, Apollo and Meg run into Commodus, who is holding a dress rehearsal for the celebration ceremony after his takeover of Indianapolis.

Commodus tries to run Apollo over with a racecar, but Apollo foils his plans with the help of an elephant called Livia. Leo and a group of Hunters rescue Apollo, Meg, and Meg’s protector, a tiny grain spirit called Peaches. They also take along Lityerses, the disgraced commander of Commodus. Lit tells them Commodus knows the exact location of the Waystation since he had trackers placed on the griffins. Commodus will attack the Waystation the next morning.

The Hunters, rescued demigods, and other inhabitants fortify the Waystation for the attack. Apollo and Meg head out to the Oracle of Trophonius to seek their prophecy. Trophonius is considered a dangerous oracle since he shows the petitioner their worst memories and fears before handing them their prophecy. Inside the cave, Meg almost dies from Trophonius’s visions. Apollo inhales her “madness” to rescue her, fulfilling the prophecy of Dodona, which said he must swallow death and “madness” in his next quest. Meg and Apollo survive, destroy the Oracle of Trophonius at his request, and head back to the Waystation, which is under attack. The only way to defeat Commodus is by revealing Apollo’s godly form, which is pure light. As a human, Apollo doesn’t have many magical powers, but he manages to focus his mind and turn into a god for a microsecond. Commodus, who has arrogantly kept his eyes open despite Apollo’s warning, is blinded. He stumbles out of a window and vanishes.

Meg sits on the Throne of Memory and recounts the prophecy, which is in the form of a Shakespearean sonnet. According to the prophecy, Camp Jupiter in California, the training school for the Roman demigods, is in trouble. Apollo must first go to the American Southwest, where he will find the third emperor and the third oracle. Meg must find her extended family. A satyr will be their guide in the process. They must then return to Camp Jupiter. Apollo and Meg bid everyone goodbye, and Meg summons a satyr to guide them. This turns out to be Grover Underwood, an important character in the Percy Jackson universe. The rest of the action continues in The Burning Maze, the next book in the series.