Grey recalls that she learned of her status as a well at age four, when she first practiced “tethering” to her father’s guard, Iowain, and sending him magical power. Years later, after her family’s deaths, the orphaned Grey offered her power to a young Kier, shocking him with her strength.

In the present, Grey lies in ambush with Kier and their company near the Iolis River, waiting for the Luthrite convoy. When the carriages approach, Kier signals the attack. Grey and Kier fight through enemy lines, with Grey wielding her sword while feeding Kier massive amounts of magical power. After finding the first two carriages empty, Kier is injured and uses a torrent of Grey’s magic to kill multiple enemies at once.

In the third carriage, they find the resource: a thin teenage girl, bound and gagged. Grey watches as Kier carries the girl out, removes his own armor, and offers it to the girl to protect her. When Grey turns away, the girl stabs Kier with his own barbed dagger. As the girl is led away, Grey rushes to Kier’s side and forces him to siphon power from her so that he will stay alive as they limp back to camp. Halfway back, Hand Ola Et-Kiltar and her mage, Brit Wyvern, help to support the wounded Kier and grow alarmed at how much power Grey is providing. When Kier orders Grey to break the tether before she drains herself completely, she reluctantly obeys.

The narrative shifts to a point six years earlier. An 18-year-old Grey works as a healer in a military infirmary, having been separated from Kier after training. She hasn’t heard from him in months and fears that he is dead. When summoned to Captain Pickett’s office, she finds Kier waiting; he is now a lieutenant. Pickett informs her she has been reassigned as Kier’s Hand.

Outside, Kier pulls Grey into a broom closet and embraces her. He explains he acted selfishly by requesting her as his Hand. Grey offers her condolences for his brother Lot’s death. As they leave the camp, Kier warns her that their new post is dangerous. He requested her specifically because he trusts her and wants to protect her from being paired with a mage who might exploit or harm her. Kier formally asks Grey to be his Hand and companion, and she accepts.

The narrative returns to the present. At the infirmary, lead healer Leonie helps Grey out of her bloody armor and gives her a nutrient sludge to replenish her depleted power. An assistant reports that Kier left his last words, but Grey refuses to read them. She performs emergency surgery to repair his internal injuries, with Mare Concord quietly appearing to assist. After the operation, Mare questions Grey’s unusually high power capacity and notes that exceptional wells must be reported to higher command, as they may have engaged in the forbidden binding ritual that pairs a mage exclusively with a single well. Exhausted and cornered, Grey leaves without being properly dismissed.

In her tent, Grey collapses and dreams of being a child in a stone basement with a boy made of fire. In the dream, the boy makes her promise to let him and some unnamed others go. Suddenly, the entire world explodes. 

Grey wakes after 12 hours and returns to the infirmary. While Kier sleeps, she covertly uses her power to accelerate his healing, mending the scratch on his cheek. When he wakes, Leonie arrives with news that Attis has requested Kier’s presence. She orders Grey to clean up and eat first.

In Attis’s office, Master Attis reprimands Kier for his recklessness during the mission. Noting that Grey and Kier’s power resembles the power of an illegally bound pair, she threatens an investigation. Kier deflects by arguing that Attis sent them into danger without adequate information. Attis sets aside her suspicions, explaining that she needs their exceptional pairing for a critical assignment. She suspects that the prisoner is Maryse of Locke, the supposedly dead daughter of the Isle’s last High Lady.

Kier protests that the known survivor is rumored to be the son, Severin Locke, but Attis speculates that the letter from Severin was forged. The mission is to escort the girl to High Lord Scaelas on the eastern coast—Grey and Kier’s childhood home. 

Upon returning to their tent, Kier begins packing to desert the army entirely. He reminds Grey of his promise that she would “never have to go back there” (68). Grey angrily refuses to abandon their duty. Kier argues that delivering the prisoner will risk Grey’s true identity being discovered. After the Isle’s destruction, relatives of Locke’s ruling family across Idistra were hunted and killed in the other nations’ misguided attempts to restore magic to the world. Kier pulls Grey close and whispers her secret: that she is the real Maryse of Locke.

To avoid Kier after their argument, Grey volunteers at the infirmary and silently reflects on her true identity. Born Gremaryse, the daughter of Locke’s High Lady, she adopted the alias Grey after the Isle’s destruction. Her mother held the title “Locke” and served as the heart of the nation, and that name died with her. After the orphaned Grey was found by Scaelan soldiers and placed with a young widow named Imarta, she met Kier’s family, who helped raise her alongside their sons.

Now, Leonie teases Grey about her devotion to Kier, and the two women acknowledge their one-time romantic encounter, affirming that they are now just friends. Grey worries that Kier values her only for her power. To thank Leonie for her friendship, Grey gives her a tender goodbye kiss. She then finds Kier, who privately reveals that he knows about her past with Leonie. He says it wouldn’t matter to him if she were in a relationship, and his comment hurts Grey, who secretly wants him to care for her romantically.

Kier apologizes for their earlier fight and expresses concern that she nearly drained herself to save him. He reveals that Mare Concord threatened him with retraining. Grey admits to being rude to Mare. Kier cups her face and kisses her forehead.

That night, Grey waits for Kier to fall asleep before sneaking out. She goes to the prisoner tent and lies to the guards to gain access to the captive girl, who attempts to intimidate Grey by claiming that she can smell the power on her. However, Grey knows this is a bluff; wells cannot detect dormant power in others, and not even Grey’s mother could do this.

Grey puts her dagger to the prisoner’s throat and threatens to kill her if she ever harms Kier again. Grey then returns to her tent and climbs into Kier’s bedroll, making him swear an oath that he will not die. Kier responds by swearing on her true name (Gremaryse Pellatisa Carnelion Masidic Locke) and on her taken names (sworn Seward, Grey Flynn). It is the first time since their illegal binding ritual that she has heard his name spoken alongside hers. Comforted by the oath, Grey settles against him.

Attis outlines their journey: a two-to-three-week trek on foot across the mountains to Grislar, near the Bay of Locke. They must pose as pilgrims to avoid detection by other nations seeking the prisoner. Kier demands three additional companions. Attis offers a reward of six months of leave upon mission completion, but Kier counters with an audacious demand: honorable retirement for himself and Grey. Though shocked, Grey silently encourages him through their tether. She envisions a peaceful future but fears that without their military duties, they would have no reason to remain together. Attis, recognizing that the mission will likely result in the pair’s deaths, agrees to Kier’s terms and provides a sealed document guaranteeing their freedom. Kier selects Hand Ola Et-Kiltar, mage Brit Wyvern, and the non-magical “typic” officer Eron Fastria to accompany them.

At the infirmary, Leonie privately tells Grey that the prisoner shows signs of rough treatment and continental dental work: evidence that suggests she may be an impostor, not the real Maryse. Leonie reveals her suspicion that Grey is not a normal well. They embrace, and Leonie asks Grey to write if she can.