Heir of Fire is the third installment in Sarah J. Maas’s Throne of Glass series, which comprises seven books in total: Throne of Glass (2012), Crown of Midnight (2013), Heir of Fire (2014), Queen of Shadows (2015), Empire of Storms (2016), Tower of Dawn (2017), and Kingdom of Ash (2018). This high fantasy novel can be categorized as new adult fiction due to its graphic violence and adult themes, which include Redemption Through Self-Acceptance, Staying in Control, and Oppression Versus Freedom.

American author Sarah J. Maas was born in 1986, and Throne of Glass is her debut series. It has received critical acclaim and has been translated into 35 languages. Maas’s other works include the A Court of Thorns and Roses new adult fantasy series and the Crescent City adult fantasy series, which have also gained popularity. Several books from the Throne of Glass series earned the Goodreads Best Young Adult Fantasy and Science-Fiction award, including Heir of Fire in 2014. Maas credits the tale of Cinderella as her inspiration for the series, with Celaena representing a destitute princess, although with a grittier tone and darker themes.

This guide refers to the 2014 Kindle edition.

Content Warning: The source material and guide feature depictions of physical abuse, animal cruelty, animal death, graphic violence, mental illness, and death. 

Plot Summary

The story unfolds in the fantasy world of Erilea, which is inhabited by humans and Fae. Ten years before the events of the main series, the human King of Adarlan attacks the Fae kingdom of Terrasen and assassinates the Fae royal family. The series’ protagonist, Aelin Galathynius, is the sole surviving royal and the rightful heir to Terrasen’s throne. However, she suppresses her traumatic past, living as a human and going by the name Celaena Sardothien. 

In Throne of Glass, the 18-year-old Celaena wins a tournament to become the Champion of the King of Adarlan. This position makes her the ruler’s personal assassin for four years, although she secretly opposes the cruel King because he murdered her family. During her adventures, she befriends Dorian Havilliard, Adarlan’s Crown Prince; Chaol Westfall, Captain of the Guard to the King of Adarlan; and Princess Nehemia Ytger of Eyllwe, whose nation is oppressed by Adarlan. 

In Crown of Midnight, a rebel leader named Archer Finn orchestrates Nehemia’s assassination because she opposed the extreme methods he wants to use against the King, and Celaena kills him to avenge her friend. Dorian learns that he possesses magic and must keep his powers secret because his father will execute him if they’re discovered. Chaol uncovers that Celaena is the Lost Queen of Terrasen, but he conceals her identity because the King of Adarlan would see her as a threat to his dominance over Erilea. To protect her, Chaol persuades the monarch to send Celaena on a mission to assassinate the royal family of Wendlyn, a kingdom that lies across the Great Ocean.

When Heir of Fire opens, Celaena is in Wendlyn. She uses her mission as an opportunity to search for answers about the Wyrdkeys. These ancient magical artifacts control the gates to the homeland of the Valg, malevolent demons that can inhabit a host’s mind and control them. The King of Adarlan wants to open the gates to use the demons’ power. 

While in Wendlyn, Celaena is found by Rowan Whitethorn, a Fae prince who serves Maeve, the immortal Fae queen and Celaena’s distant aunt. For years, she has been searching for Celaena, who possesses a powerful ability to control fire. Maeve agrees to answer the young girl’s question only if Celaena trains with Rowan to prove she is worthy of entering Doranelle, Maeve’s hidden Fae city. Celaena and Rowan hate each other at first, but through their investigation of strange murders in the area, they realize that they are both struggling with their grief and trauma and decide to work together. Their friendship is cemented when they fight together against three Valg princes and defeat them by using Celaena’s fire magic.

Celaena slowly embraces her identity as Aelin Galathynius, the Lost Queen of Terrasen, whom everyone presumed dead after the King of Adarlan had her parents murdered 10 years earlier. She eventually confronts Maeve, who reveals her own desire to get the Wyrdkeys, and forces her to break Rowan’s Blood Oath. He then swears his loyalty to Celaena. At the end of the book, Celaena decides to return to Adarlan to find the third Wyrdkey and raise an army against the King to reclaim her rightful throne and free the world from the Valg. 

Meanwhile, in Adarlan, Dorian struggles to keep his magical powers hidden from his father. He develops a romantic relationship with Sorscha, a healer, who helps him conceal his powers. When he learns about Celaena’s true identity, Dorian remains loyal to their friendship and encourages Chaol to pick a side.

On the other hand, Chaol struggles to reconcile his loyalty to Dorian and his desire to rebel against the King’s cruelty. He enters an alliance with Aedion Ashryver, one of the king’s generals, who secretly works with the rebels while waiting for the return of his cousin, Aelin. Their investigations reveal how the King made magic disappear 10 years earlier. They plan to undo the spell and free magic again.

At the end of the book, the King forces Dorian to reveal his powers by executing Sorscha. Then the king puts him under one of the Valg’s control. However, Dorian is first able to help Chaol escape. The latter goes into hiding and vows to fight against the king and free his friends, as Aedion is also taken prisoner.

A third main plot is introduced through Manon, the heir of one of three deadly witch clans, and her loyal coven, the Thirteen. The king has promised the brutal and cruel Ironteeth witches wyverns in exchange for serving him during the upcoming war. Manon, the witches’ greatest warrior, unexpectedly picks a small but cunning wyvern with whom she bonds. Manon’s awareness of the cruelty and injustice of the Ironteeth witches develops throughout the story, culminating when she rebels against her grandmother and clan leader during the climactic War Games. Although she is crowned Wing Leader, it is a bittersweet victory that foreshadows her break from the Ironteeth witches in Queen of Shadows.