Mara, an Oathtaker, trained to protect Ehyeh’s chosen, the Select, those designated to carry His ways of life and freedom through the ages, is drawn from her intended path. She discovers a wayfarer’s hut. Thirteen grut, underworld beasts, surround it. As she kills each, it goes up in a flash of fire. Thereafter left with a single weapon—her Oathtaker’s blade—a weapon infused with a magic that will live for so long as she does, Mara steps inside. There, she discovers Rowena, the current ranking member of the first family of the Select, in labor. Rowena bears twins, although no Select had ever before had twins. She names them Reigna (derived from the word “reign”) and Eden, releases her power as leader of the Select to them, and then dies.
Though Mara knows of no Oathtaker with more than a single charge, she swears a life oath to protect both infants. In exchange for her vow, Ehyeh bestows upon her, “continued youth” for so long as her charges live, and attendant magic—powers that will make themselves known to her over time. Upon the death of her charges, Mara may begin her life anew, but in the meantime, she may not be unequally yoked—she may not bind herself to another. Ehyeh confirms Mara’s vow with an earthshaking.
The hut door bursts open and a man, Dixon, enters. Upon finding Rowena, his former charge, now dead, he blames Mara. The two enter into a weak alliance to work together to usher the infants to safety. When they find grut teeth on the ground, they collect the trinkets, as the creatures cannot harm anyone who possesses one. Then, seeking to hide all evidence of Rowena, they set the hut, with Rowena’s body inside, on fire.
The Oathtakers make their way to the home of an old couple, Drake and Maggie. From them, they learn of an Oathtaker-run mission home in Polesk for young women fleeing to Oosa from a neighboring empire, Chiran. As the women often arrive at the place pregnant, or with newborns, the Oathtakers plan to head there to find a wet nurse for the twins. Although tempted, Mara restrains herself from thinking on her past, which seeks to worry its way into her thoughts.
Previously on Rowena and Dixon’s trail, Gadon and his men, who had called up the grut, arrive at the home of the oldtimers who lead them to believe that Dixon and Rowena had visited them, and that Rowena had born her child. In fear, the oldtimers tell the men that the two left for Polesk. Gadon sends one of his crew ahead in search of them, then kills the couple.
When Gadon’s man intercepts the Oathtakers, they learn that someone from the palace of the Select at Shimeron, home of the first family, enlisted Gadon’s assistance. Mara and Dixon dispose of the man, then stop for the night. Mara, now weary of Dixon’s surly behavior, tells him to leave her. He apologizes for having unfairly blamed her for Rowena’s death, then swears he would die for the twins. To Mara and Dixon’s amazement, Ehyeh confirms Dixon’s vow with an earthshaking. Since Mara is already the twins’ assigned Oathtaker, the two are troubled as to the meaning of the confirmation. They make peace, then Dixon suggests that his friend, Edmond, might be of help. The two grew up like brothers after Dixon’s father led a successful prosecution against Edmond’s father for treason against the Select. Enamored with Mara’s strength of spirit, Dixon allows her to believe he had loved Rowena, as he thinks it will help to keep a distance between them.
The Oathtakers arrive at the mission home where they meet Nina, a young Chiranian. Grieving over the death of the child she bore while escaping Chiran, Nina swears to protect the twins with her life. The Oathtakers are shocked when Ehyeh also confirms her oath, with an earthshaking.
While in Polesk, meeting with Dixon’s old friend and mentor, Ted, Mara is startled when a compact she carries that had belonged to Rowena, starts “buzzing.” When she opens it, a woman’s visage greets her. Dixon recognizes Rowena’s friend, Lucy, who reveals that she has prepared a safe place for Rowena. Mara informs Lucy of Rowena’s death, and of the twins’ birth, then makes plans to join her.
The Oathtakers head for sanctuary. There, they discuss the significance of the first- through seventh-born children of the Select, and ponder over the difficulties that one who is a sixth-born—one most interested in pursuing his own desires—could cause. Mara comments on a dream she had the night before, in which a woman took the infant girls from her. She had not recognized the dream as the working of some attendant magic, bringing her a warning, but Dixon does. He insists she leave immediately. As she exits through a back door with Nina and the twins, Lilith a sixth-born of the Select, Rowena’s next older sister, arrives.
Hearing of her sister’s death, Lilith assumes Rowena’s child also died, and that she, Lilith, is now the ranking member of the Select. She bands Dixon, cutting off all magic getting to or from him. He, now sure Lilith sent the assassins after Rowena, willingly accompanies her to the palace in Shimeron, so as to avoid raising her suspicions, although he grows fearful that she intends to make a scapegoat of him.
At the palace, Dixon finds his friend, Edmond, who insists he is friendly with Lilith so as to keep the peace. Dixon also discovers another friend and fellow Oathtaker there—Basha. Dixon meets Basha at the falls where her charge, Rowena’s sister, Therese, was believed assassinated some years back. Her body was never found. After a rustling in the underbrush momentarily interrupts Dixon and Basha’s conversation, the two speak freely. Basha believes Therese still lives, because she occasionally feels her bond to her charge. Further, she believes Lilith was behind the assassination attempt on Therese’s life. Dixon reveals nothing of his suspicions about Lilith, or about Mara and the twins.
Mara and Nina check into an inn. They learn from the local fliers, that Lilith holds Dixon, and that he will be tried for treason. Then Mara discovers more attendant magic powers: she can taste and smell color. As a consequence, she believes a woman who watched her earlier that evening during dinner, is outside her door. Fearing for the infants, Mara arms herself, then opens the door. The woman standing just outside, introduces herself as Therese. Recollecting details from a dream, one in which she rustled through some brush, then felt as though she was physically present with Dixon and Basha at a falls, Mara tests the woman with information she had learned from her “dream.” When Therese proves true, and discloses that she has been staying with Lucy, Mara reveals her true identity and that of the infants. Joyous over the children’s survival, Therese swears a life oath to protect them. Once again, the earth shakes with Ehyeh’s confirmation.
Later, while seeking rest, Mara “awakens” in a room where Dixon soon arrives. He informs her that Lilith captured him, took him to the palace, and will have him tried, but Mara disappears before he can think to have her remove the band Lilith put on him to block his magic powers. Back with Nina, Mara discovers she returned from her “dream” carrying Dixon’s flint.
Lilith meets with her spirit guide, Daeva, lord of the underworld. He informs her that Rowena’s child lives, and that Rowena released her power to her child before she died. As a consequence, Lilith is not the legitimate new ranking member of the Select. Then he assures Lilith that there is still a way for her to become the ranking member so that she may reign over Oosa, and he endows her with dark magic.
Lilith, furious to learn the true facts, questions Dixon. When he refuses to tell her of the child’s whereabouts—as Lilith is unaware that Rowena bore twins—she tortures him with her dark magic.
Mara and Nina, with the infants, travel toward Lucy’s with Therese and her bodyguards, Jules and Samuel. When the group stops to rest, Mara again finds herself magically transported to Dixon’s side, although now he is in a cave of sorts, and unconscious from a severe beating. When Basha shows up there to see to Dixon, Mara recognizes the woman from her dream, when Basha spoke with Dixon at the falls. When a maid arrives to warn Basha that Lilith is on her way to see Dixon, Mara returns, magically, to her friends. Moments later, she discovers more magic—the power to heal. She longs to return to Dixon to heal him. Then, realizing that she magically traveled back from her first visit to him carrying his flint, Mara surmises that she might rescue him from Lilith’s clutches. She ponders whether she wants him with her to assist her with the infants, or because of her growing interest in him. Later, Jules and Samuel swear to protect the twins with their lives. Each receives Ehyeh’s confirmation of his vow, when the earth shakes.
When a storm erupts, the travelers find shelter in a barn built partially into the ground. There, Mara discovers a grut guarding a path that extends deep into the earth. As the grut tooth she wears protects her from the beast, Mara nears, then kills it. Then she finds, back in the cave, a shrine with an oracle—a book—that refers to a seventh seventh “and she who is but is not.” Mara recollects something that Rowena had said when Eden was born—that the child was of a seventh pregnancy, but was not a seventh-born child.
Mara discovers that the book provides the identical message on every page: “Go.” Thinking it means she is to go to rescue Dixon, she magically travels again, back to his side. Once again, she finds Basha with him. Although Mara tries to heal him, and to take him away, she is unable to do so. To test her powers, she urges Basha to travel with her. Upon Basha’s agreement, the two instantly return to the barn. There, Basha and Therese are reunited. Basha then recollects that Dixon is banded. Therese informs Mara that as Oathtaker to the twins, who are the rightful ranking Select, she possesses the power to remove the band.
Mara magically returns to Dixon’s side. She removes his band. Just then, the maid, Adele, arrives to warn Basha, who she knew had gone to see Dixon, that Lilith is on her way to see him. Moments later, Lilith enters. Adele grabs Mara and is caught up in the Oathtaker’s magic. Back with her friends, grateful that Lilith did not also tag along for the magic ride, Mara heals Dixon and then, passes out. Later, he awakens her from her magic hangover.
Mara learns that a few years prior, Lilith had a son, and that when circumstances suggested the child was not safe with her, Rowena took him away. No one knows his father, but Therese informs the others that the child stays with Lucy. Both Basha and Adele swear life oaths to protect Rowena’s infants. Each receives Ehyeh’s confirmation of her vow.
Lilith meets with Daeva. He agrees to have the Chiranian leader, Zarek, who also serves the underlord, provide her with an army. When it arrives at the palace, Lilith tells the soldiers her plan: she will tell the people that someone is trying to pawn off a fraud as a new seventh seventh, then will encourage the people to give up the child she seeks. If they do not, she will kill all the infant girls. Her venture will begin in Polesk, but she will travel throughout Oosa to do the same elsewhere, as necessary, in her search for the child.
Erin, Nina’s sister, and a slave to Zarek’s soldiers, breaks free and runs to Polesk. She meets a woman, Hattie, who rushes her to the mission home where they find Dixon’s friend, Ted. They inform him of Lilith’s plan. Ted relays that Lilith could cut off the twins’ rightful line of rule if she kills them with a living Oathtaker’s blade. Then, believing that sanctuary is the only safe place for the children of Polesk, Ted attempts to save them, but he is unsuccessful. Lilith’s soldiers begin to follow through with her plan.
Wanting to dedicate the infant twins at a sanctuary, and to confirm that one of the three artifacts intended for the ranking member of the Select, the great crown, is still in the City of Light where Rowena left it, Mara leads her group to the city. They arrive at The Clandest Inn, owned by Dixon’s friend, Ezra, a spymaster. Mara worries over the attention the barmaid, Celestine, pays to Dixon, though she reminds herself once again, that while he is now free of the oath he’d sworn to protect Rowena, she is still bound to her oath to protect the twins. For the first time since the girls’ birth, Mara allows herself to think on a child she had abandoned in her past.
Mara and Dixon learn, along with Ezra, that Lilith travels with an army, that she seeks Dixon, and that she claims someone is trying to pawn off a fraud as a new seventh seventh. Mara tells Ezra about the twins. Delighted, he swears a life oath to protect them. Ezra receives Ehyeh’s confirmation of his vow in the form of an earthshaking. Then the three make plans for Ezra’s spies to spread false rumors of Dixon’s whereabouts throughout Oosa, so as to lead Lilith astray.
When Mara takes the twins to sanctuary, two oldtimers, Leala and Fidel, intercept her. They recognize the twins as fulfillment of prophecy and swear life oaths to protect them. Ehyeh confirms the oldtimers’ oaths, and they join Mara’s entourage.
A guest arrives at Lilith’s camp. He believes he can find Dixon, that Dixon will trust him, and that he can deliver the man to Lilith. She uses her dark magic on her guest, so that he cannot reveal his true intentions, and then sends him off in search of Dixon.
Meanwhile, seeking information about Lilith, Mara and Dixon travel magically to Polesk. There, they learn from Ted, of Lilith’s venture, and of the deaths of many infants.
Lilith’s soldiers capture Velia, an Oathtaker. Possessing the power to tell truth from falsehood, Velia learns of Lilith’s plan to kill Rowena’s seventh-born child. She agrees to accompany the woman, so as to gather evidence against her to take to the Council.
Mara confirms that the great crown is in the City of Light, and she knows Lucy has the second of the artifacts, the sword, with her. When the oracle once again tells Mara to “Go,” she ponders whether it is telling her to go to Shimeron in search of the last of the artifacts, the scepter, where she believes it to be, or if it is telling her that she should go away from Dixon, whom she has come to love. She plans a trip to Shimeron and asks Basha, who was a palace regular, to accompany her there.
Concerned over Mara’s state of mind, as she has been inseparable from the twins since returning with him from Polesk, Dixon encourages her to go walk with him. While out, she breaks down weeping. She tells Dixon that it pains her to leave the girls, as she left a child once before—one she’d sworn to care for. While comforting her, he confesses his love for her. Though she loves him in return, the two know they cannot act on their feelings, as Mara remains bound to her oath. Heavy hearted, they agree not to speak of such things again.
Mara and Basha travel magically to Shimeron. There, Mara discovers she can create crystals that make powerful weapons, and that allow her and Basha to communicate silently, by magic. They search Lilith’s chambers. When Daeva shows up there in Lilith’s looking glass, Mara casts him out with a crystal. Then she finds the scepter. She takes it, and also some books she finds at the palace, back to the inn.
Nina, to whom the ways of Oathtakers are largely unknown, asks Mara why she avoids Dixon when everyone knows they love one another. Mara tells her the truth: that subject to her oath, she is not free. Acting on her feelings would be an act of treason. At a minimum, it would mean losing the girls, and that is not a prospect she will consider.
Mara sends part of her group ahead to Lucy’s with the scepter, for safekeeping, along with some books she wants to study later, including one that discusses an Oathtaker’s oath, and its “rules and exclusions.” As the group leaves, Dixon’s old friend, Edmond, arrives. Learning of the twins, he tells Dixon when Lilith is due back in the City of Light, then insists that he must set off for urgent business, but that he will return shortly.
A guard escorts Velia to Lilith’s wagon, where Lilith introduces Velia to Edmond who has brought to her, news of Dixon’s whereabouts and of Rowena’s twins. Lilith asks Velia to accompany her and Edmond on a trip. They, with a single guard, Jabari, set out. When Lilith becomes suspicious of Velia’s intentions, Jabari reveals to Velia, his true identity. He, also, is an Oathtaker. He joined Lilith’s solders earlier, in appearance only, to gather evidence against Lilith to take to the Council.
Lilith, Edmond, Velia, and Jabari, arrive in the City of Light. They check into an inn. Edmond messages Dixon, pleading for him and Mara to meet him at sanctuary the next day. There, he will share with them, news of Lilith. Although the Oathtakers had planned to leave the city the next day, at the oracle’s urging to “Go,” they agree to the meeting.
Hiding her true identity, Lilith checks in at The Clandest Inn, then watches out a window as Mara and Dixon leave to meet with Edmond. Lilith goes to Mara’s suite. She stabs Erin, tortures Samuel with her evil magic, and then threatens Nina, demanding that she help her to get the twins to sanctuary. Meanwhile, Velia awakens at the inn, practically incoherent. Lilith had drugged her. Worse yet, Velia discovers, Lilith stole her Oathtaker’s blade.
When Mara and Dixon meet with Edmond, Velia arrives at sanctuary. Distraught because she does not know where at sanctuary, Edmond’s meeting with Mara and Dixon is to be held, Velia goes to the inner prayer room to seek Ehyeh’s assistance. When an old woman asks her what is wrong, Velia tells her that she must warn two Oathtakers. When she reveals their names—Mara and Dixon—the old woman, Leala, rushes Velia to the meeting.
In the meeting room, Velia accuses Edmond of seeking revenge on Dixon, and of assisting Lilith. He denies her accusations, claiming that Velia cannot even prove she is an Oathtaker, as she has no Oathtaker’s blade. Although Dixon finds Velia’s accusation impossible to believe, Mara wonders. She asks Edmond to reassure her. Feigning outrage, he swears he would protect the infant twins with his very life. When the earth does not shake, Mara knows that Edmond betrayed them. She grabs Dixon and they magically transport back to the inn. There, they find Samuel, who is just able to relay to them that Lilith took the twins to sanctuary.
Returning immediately by magic, to sanctuary, Mara can smell and taste Lilith’s ever-present red clothing. Though they make her ill, the smells and tastes draw her to the inner prayer room. After fighting off a pack of grut that bursts forth, Mara makes it to the door. Velia warns her that Lilith is inside, then recalls that the woman has her Oathtaker’s blade. They all understand: Lilith can use it to cut off the girls’ line of power.
Dixon and Velia enter the inner sanctuary through its front door. There, they find Lilith with Nina and the twins. Velia attacks Lilith, but Lilith spares the Oathtaker, as she needs her alive when she uses her blade to kill the twins on the altar, as Daeva has commanded her. Believing that the grut she had called up, attacked Mara, Lilith does not expect Mara to secretly enter the inner sanctuary through a back door.
Dixon distracts Lilith while Mara enters and then sends Nina and the twins out to safety. When he urges Lilith to turn back to Ehyeh, Lilith uses her dark magic on him. Mara announces her presence, but Lilith refuses to stop torturing Dixon. Mara throws her blade. It meets its mark, and Lilith goes up in flames.
Heavy hearted, as she has concluded she can no longer bear having Dixon so near, yet out of reach, Mara determines that they must part ways. But first, she calls a Council meeting to claim her rightful place as its leader, and to prove the twins’ identity. When the meeting is to begin, Mara discovers that Lucy is a Council member, a fact Dixon had kept from her, as an oath bound him to secrecy.
Mara presents her witnesses. While testifying, Nina reveals that she recognized Lilith, whom she’d met in Chiran. There, Lilith acted as consort to Zarek, and went by a different name. Rumor had it that when Lilith left Chiran, she was pregnant. Mara and Dixon understand: Lilith bore Zarek’s child, the one now living with Lucy.
As the hearing is closing, Lucy interrupts. There is an item of business remaining. Reports are that Mara and Dixon have fallen in love. Mara tells the Council that they need not worry, as Dixon will be leaving her. He, caught by surprise, is distraught.
Lucy laughs lightly, then composes herself. She questions Mara and Dixon about what it means to be unequally yoked. They assure her they understand. Lucy then pulls out a book that Mara had sent ahead with a part of her group, along with the scepter, to Lucy’s. The book discusses the Oathtaker’s oath, its “rules and exclusions.” Lucy tells Mara and Dixon that, as they both swore a life oath to protect the same of the Select, and as Ehyeh confirmed the oath of each of them, they are not unequally yoked. In fact, they are free to be together.