Plot summary
20-year old Violet Sorrengail is the youngest daughter of General Lilith Sorrengail, the commanding general at Basgiath War College in the kingdom of Navarre, where students choose to join one of four military Quadrants: infantry, healer, scribe, or dragon rider. Navarre is guarded by wards which are powered by dragon magic and protect the kingdom from all other magic, including attacks inflicted by gryphon fliers from the neighbouring kingdom of Poromiel.
Despite years of training to be a scribe like her late father and her many physical weaknesses, including chronic pain and fragile joints stemming from an illness in her infancy, Violet is mandated by her mother to join the Dragon Riders Quadrant. All cadets in the Rider Quadrant must endure deadly challenges and a ferociously competitive environment to bond with a dragon that they will eventually be able to telepathically communicate with and receive a unique magical power (signet) from. Violet's older sister Mira, a lieutenant in the Navarrian military and seasoned dragon rider, prepares Violet for conscription day by gifting her an impenetrable armoured corset made from dragon scales. She also gives Violet a journal containing advice on surviving the Rider Quadrant that belonged to their older brother Brennan, another dragon rider who was killed six years before in the Tyrrish Rebellion. All children of rebels are denoted with tattoos, signifying them as 'marked ones,' and are forcibly assigned to the Rider Quadrant as a form of institutionalized retribution. Mira cautions Violet to be wary of the marked ones, who will try to kill her as revenge against their mother, who was pivotal in ending the rebellion.
On conscription day, Violet crosses the parapet, a narrow wall separating the Rider Quadrant from the rest of the college. She befriends Rhiannon Matthias, but narrowly escapes an assassination attempt from Jack Barlowe, who views her as a liability to the quadrant. She also meets Xaden Riorsan, a third-year cadet and the son of Fen Riorsan, who led the Tyrrish Rebellion and was executed by Violet's mother. Once in Basgiath, she is reunited with her childhood friend and longtime crush Dain Aetos, who is concerned for her safety and attempts to persuade her to move to the Scribe Quadrant. Violet refuses however, and is eventually assigned to Fourth Wing alongside Rhiannon, with Xaden as their wingleader. Dain, a second-year, is their squad leader and Violet learns his signet is memory reading, which she agrees to keep secret due to its classified status.
Cadet training begins and, while Violet excels in academic studies due to her training as a scribe and intellectual prowess, she struggles during sparring lessons and is targeted by marked ones who blame her for her mother's execution of their parents. To overcome her physical disadvantages, Violet offers to teach Rhiannon history in exchange for combat training, and befriends two other cadets in their squad, Ridoc and Sawyer. Using Brennan's journal, she finds out her sparring opponents before combat challenges and begins to poison them to avoid injury. One night, while foraging for ingredients, Violet eavesdrops on a clandestine meeting among a group of marked ones, who are prohibited from meeting in more than groups of three. Xaden, a shadow wielder, discovers her and demands her silence in exchange for a future favour. Later, Xaden challenges Violet during a sparring match but, to her surprise, does not attempt to kill her and instead points out the errors in her sparring technique, telling her she must to learn to fight if she wants to survive the Rider Quadrant.
Violet's squad is granted an audience with the dragons before Threshing, where they are surprised to find a very small and rare golden feathertail, a breed known for its resistance to bonding with humans. During Threshing, Violet learns that Jack plans to kill the golden dragon due to its perceived weakness. She intervenes but is attacked by Jack and his accomplices. Xaden and his dragon, Sgaeyl, arrive and observe the fight. Violet successfully fends off her attackers, before a large black dragon named Tairn arrives and kills the remaining cadets, bonding Violet and carrying her back to the college. Astonishingly, the golden dragon, Andarna, also bonds with Violet, making her the first rider in history to command two dragons. She learns that Tairn is Sgaeyl's mate and that, as mated dragons cannot be separated for long periods of time, Xaden suddenly has an unexpected stake in her well-being. She also learns that Tairn's previous rider was a lieutenant named Naolin, who died trying to resurrect Brennan after his death during the rebellion. Dain kisses Violet, who regretfully realizes her feelings for him have waned.
Despite her improved physicality, Violet struggles to maintain her balance on Tairn during flying practice. Violet becomes increasingly frustrated with Dain's overprotectiveness and accuses him of thinking her weak. One evening, Tairn awakens her as six unbonded cadets attempt to kill her in her bed. Andarna intervenes, freezing time until Xaden comes to her rescue. Violet reveals to Xaden that a senior cadet admitted the intruders to her room. Xaden confronts the cadet before the entire student body, resulting in her execution. Following the assassination attempt, Xaden enlists Liam, his foster brother and a fellow marked one, as Violet's bodyguard. Privately, Violet and Xaden meet with their dragons, where Violet learns she can telepathically communicate with Sgaeyl due to her bond with Tairn and that Andarna is not a rare breed, but a child. Her time-stopping power must be kept secret until she matures, as it is vulnerable and could be stolen. After weeks of anxious waiting, Violet finally begins to receive power from Tairn, but has not yet learned how to shield her emotions from her dragon's. One night, spurred on by Tairn's feeling for Sgaeyl, Violet becomes overwhelmed and kisses Xaden. Soon after, Jack attempts to kill Violet during a sparring match, but she narrowly escapes by exposing him to an allergen.
The annual Squad Battle arrives, which sees cadets vying to steal coveted items from their foes. Violet's squad seizes General Sorrengail's map of military outposts, earning them the chance to shadow soldiers on the front lines. They fly to Montserrat, a military outpost, where Violet reunites with Mira and realizes that she and Xaden have the power to communicate telepathically due to their dragons' bond. Their visit is cut short by an attack from gryphon fliers from Poromeil. Later, during a capture-the-flag game, Violet saves Liam from Jack's deadly attack by freezing time from Andarna. In the process, she manifests her signet, lighting wielding, which she uses to kill Jack. That night, she and Xaden give into their feelings for each other and become intimate, but Violet later tells Xaden that she cannot have a sexual relationship without becoming emotionally attached and will only sleep with him if he is also willing to risk his feelings. She begins to ask him personal questions to develop their relationship. After seeing Xaden and his cousin Bodhi returning from a flight after curfew, Violet asks him where they went and he tells her they went to Athbeyne, a military outpost outside of the wards, but does not tell her the reason for their visit.
Reunification Day arrives, a celebration of the defeat of the rebels and the triumph of the rebellion. Violet seeks Xaden, who is grieving his father's death. They confess their mutual attraction and have intercourse, but are interrupted by the announcement of the War Games' final stage. Xaden leads part of their squad, comprised entirely of marked ones, and Violet to an outpost outside the empire. They encounter gryphon fliers and Violet learns that Xaden has been providing them with weapons, smuggled out of Basgiath. Although she is devastated at his betrayal, Xaden tells her that Poromiel is being attached by venins, evil creatures that corrupt magic and whom Violet and most of Navarre believed only existed in folklore. He reveals that Navarre's leaders know the truth but are keeping it hidden as their wards protect them from venin. The squad receives a missive from General Aetos, Dain's father, revealing that they have been lured into a trap and venin are attacking Resson, the outpost they are at. Violet realizes that Dain has been stealing her memories and that she accidentally disclosed private information about Xaden to Dain, including his visit to Athbeyne, giving General Aetos enough ammunition to suspect them of treason and trap them.
Despite the danger, Violet and the rest of the squad decide to aid the gyphon fliers against the venin attack. While they are able to evacuate the town, Liam's dragon is killed and Liam dies in Violet's arms. Violet uses her lightning abilities to kill the remaining venin, while also channelling power from a weakening Andarna to freeze time. She is gravely wounded by a venin and Xaden and the survivors take shelter in Aretia, the former Tyrrish capital believed to have been abandoned since the rebellion. Violet awakens after three days and, upon awakening, Xaden vows his loyalty and devotion to regaining her trust, but she is skeptical. She is stunned when Brennan enters the room, revealing that he is alive and welcoming Violet to the revolution. The story ends on a cliffhanger, setting the stage for the continuation in the sequel, Iron Flame.
