This is the fifth book in the Pegasus series, which follows the adventures of Emily, a mortal girl from New York who one day discovers wounded Pegasus on her rooftop. Via various adventures, Emily travels from Earth to Olympus and discovers that she is not mortal, but a divinity known as the flame of Olympus. With the help of her mortal and Olympian friends, Emily tries to maintain peace in both worlds. In the last book, Emily discovered she is actually a remnant of an ancient and wise race named the Xan. Her Xan personality is called Riza and both her soul and Emily’s reside in Emily’s body. Emily and her Olympian friends successfully managed to thwart an evil plan of the Titans, and their leader, Saturn. Saturn is condemned by his son, Jupiter, Neptune and Pluto, to eternal torture in Tartarus. Meanwhile, we encounter the Titans, Lorin and Phoebe, who were also imprisoned in Tartarus, after the Titans lost the war. 

After transforming her friend Tom into a sphinx so he could reunite with his Sphinx lover Alexis, Emily feels tired and sick and does not feel the presence of Riza anymore. Emily then befriends a night dweller called Fawn on Olympus. When Emily tries to help some night dwellers, something happens and her powers of the flame are somehow transported to Lorin, making her a second flame. Lorin tries to enter Emily’s mind and steal her power, and at the same time Lorin accuses Emily of taking her powers form her. Emily feels her rage and warns Jupiter about her. 

Emily returns to the mysterious world, Xanadu, in order to find out what is wrong with her and consult the super computer there, Arious about solutions. Riza then confides in Emily that they are dying, and will do so unless they find more flame shards to restore Riza’s powers. Apparently Lorin also shares the major part of Riza’s powers and that is making her a mortal danger to Emily. Arious tells Emily that a flame shard can be found on earth. Meanwhile Emily discovers that Olympus is being attacked once more by the Titans who now control Lorin’s flame powers. Jupiter, however, orders Emily to go to Earth and retrieve the shard. She is joined by Joel, Pegasus, Paelen, Fawn, Chrysaor and Chiron. 

The group arrives in Hawaii to retrieve the shard and there they encounter Pele, a Hawaiian deity, and the group gets entangled with Pele’s fight with her sister, Nā-maka-o-Kaha‘i. In Hawaii, the group is discovered by the sinister secret organization, CRU, which also captures Lorin, who had traveled to Hawaii in search of Emily. At the final showdown, the fight between Emily and Lorin, the Olympians and the Titans, the Xan finally arrive to stop the bloodshed. The Xan then creates a new body for Riza and she and Emily are separated. Riza remains with Emily on Xanadu and Lorin is taken to Olympus to be taught compassion.

The author wishes to emphasize the gruesome effects of war; there are no real winner and there are heavy losses on both sides. When the innocent Titan, Lorin, asks what war is, her relative struggles to explain to her why they are punished and locked away. Emily’s power, which saved Olympus, also caused devastation to the world of Titus from whence the Titans came. The power that saved is also capable of great destruction. 

This book explores loneliness and family. Emily temporarily lost touch with Riza and feels weak and lonely. Lorin lost her family on Titus when the powers of Emily struck the Titans. Fawn, a night dweller whom Emily encounters on Olympus, also feels lonely since her brother is sent as a guard to watch the Titans in Tartarus. Even Arious, the Xan super-computer, is frightened of being alone again. All three girls, from very different races, share the same feeling of loneliness and sadness. This shows that the enemy might be more similar to us than we would like to think. This motif was already explored in the series, with regards to the Nirads in the second book, and now the author emphasizes this notion again.

The parallel story of Lorin is almost the opposite to that of Emily’s. Lorin also discovers her powers and will do anything to find Emily, yet her powers are still raw. Emily rages and does all she can to protect her friends; all Lorin wants is revenge.  Lorin is manipulated by Saturn and used as a weapon against the Olympians. Lorin yearns to be complete and she realizes she needs to use her power to hurt people in order to fulfil this desire (by serving Saturn). She longs to be complete, and feels she is missing something but is not sure what it is. When Emily first discovered her power was also torn between who she thought she was (a girl form NY) and who she turned out to be (the flame and then Xan). The desire to know your own identity and be complete as a person is another trait of puberty and growing up. Lorin feels this and also is possessed by an uncontrollable rage. This happens to many adolescents who cannot shake anger that they feel (here Lorin’s condition is explained by the fact that she inherited Riza’s powers, but without her soul or mind, in contrast to Emily, who is one with Riza). The author is basically describing typical teenage behaviours, yet she weaves them into a fantasy story about girls who have greater powers than they think. Lorin also blames Emily for her own actions in an attempt to shield herself from the horrors she committed to others. She evades responsibility and tries to blame Emily for everything.

Throughout the series, a recurring motif was self-identity. Emily, who was initially an ordinary American teen from New York, discovered new power and new identity with each new book. She slowly discovers that she really is a part of the ancient Xan. In this book, she faces the most dangerous challenge to her identity, in the shape of Lorin. Lorin wishes to take Riza from Emily and thus destroy Emily. The fear of disappearing completely is a psychological fear that is shared by many adolescents. In Emily’s story, this fear receives a graphic and concrete realization through Lorin’s and Emily’s dependence upon Riza. In order to save herself and stop Lorin, Emily jumps into the heart of a volcano, where the shard is. Only after sacrificing herself (as she did long ago on Olympus, at the temple of the flame), could she be complete again. Losing who you are and finding yourself are recurring motifs in this story. It demands sacrifice and courage for one to remain true to oneself. This Christianizing element of self-sacrifice repeats throughout the series. Emily’s sacrifice is always intended for the greater good and for the salvation of her friends.

To complete the story, Emily and Riza each get a new body; Emily’s new body is created from her father’s DNA and from Diana, now her surrogate mother, along with a bit of DNA from Riza. Thus Emily becomes complete not just inwardly but also physically. While she still remembers her late mother in her heart, she gains a new mother as well and begins to heal.

At the final acknowledgment, the author again asks her readers to be compassionate and caring for all creatures and animals, especially dolphins and whales which are being slaughtered; hence the author combines the peaceful message of the book’s ending with her own environmental message, which she retains throughout the series.