Mische remembers a conversation that she had with Atroxus long ago, in which he told her that he experiences everything at once as a god. Following that conversation, Mische has always wondered how gods can care for all mortals when they see so much.

Mische and Saescha fall into the nothingness of the underworld, but Mische is pulled out by the souls of the dead, Vincent among them. He informs her that Asar’s ascension has stopped the decay of the underworld but that more threats remain. Mische wants to give up, but Vincent claims that he has helped her on behalf of Acaeja, the god Oraya’s mother served, and that Mische must follow through on her mission so that Oraya can survive. Vincent informs Mische that she has a fragment of Alarus inside her—a remnant of the thwarted resurrection spell—and that the underworld, the House of Death, has claimed her as their queen. The dead offer her Asar’s sword, which has been reforged for Mische and depicts a phoenix on its hilt. When she grasps it, an heir mark that is a twin to Asar’s appears on her arm.

Nyaxia and Asar travel to the House of Night, where Nyaxia kills the remainder of Shiket’s Sentinels, sparing the House of Night more carnage. Afterward, Nyaxia brings Asar to the home she once shared with Alarus.

The gods arrive at Nyaxia’s territory, and Shiket and Nyaxia trade threats to each other’s kingdoms. When Shiket considers waging war, Nyaxia warns her that with Asar as her ally, the dead are a limitless resource at her fingertips.

Mische relies on the whispers of the dead to find her way through the underworld. She remembers the dream she once had of “a broken firefinch in the dirt, rising up again to the sky” (532).

Asar visits the underworld and wanders. He eventually comes across a field of withered poppy flowers. He revives one, which brings him satisfaction.

Mische reaches the field of poppies and notices the single living flower, which the spirits whisper is for her. She picks it and places it in her hair.

Asar visits the underworld as Nyaxia prepares for war. This time, he goes to a temple housing a fallen guardian—a metallic bird. He takes the skull, reforming it until it resembles a small, delicate mask. Content with his creation, he leaves it in the center of the room.

Mische reaches the temple, where she discovers the bird mask at its center. The dead whisper that it was left for her, so she picks it up and places it over her face.

Nyaxia complains about the time Asar has been spending in the underworld while she prepares her vampire army to battle the White Pantheon’s human forces. Nevertheless, he returns once again to the underworld and enters Morthryn. However, the relics prevent him from venturing too far inside, convincing him that the building holds reminders of someone he no longer is. He obeys, abandoning the prison.

Mische reaches Morthryn, where she is found and attacked by Saescha, who is greatly weakened from her time in the underworld. Mische easily overpowers her, and Saescha cries, moaning for justice. Mische realizes that Saescha was never seeking justice for her own death but for Mische’s. Mische admits to failing Saescha, claims that she deserved better, and calls her the “sacrifice [she] will not make” (548). Mische then helps Saescha’s soul pass on.

Mische enters Morthryn, where she encounters a childhood version of Asar curled up with Luce. He claims that he’s too scared to leave because he will make many mistakes if he does. Mische states that mistakes are inevitable but assures him that she’ll love him regardless. Young Asar pulls his heart from his jacket pocket and offers it to Mische, who promises to treasure it. Asar fades away, but Luce accompanies Mische to the exit of the underworld.

Nyaxia orders Asar to summon the dead to fight in her army, but they resist his call when he opens the veil. Instead, Morthryn—which appears to be burning—rises from the mortal sea, bringing back the ancient kingdom of Vathysia. Asar enters Morthryn and orders it to reveal the traitor that it hides. When it refuses, he tears through the castle with force until he discovers Mische. When he meets her eyes, he is unable to harm her despite the urging of Alarus’s relics. Eventually, he remembers her and urges her to take the god’s heart.

Mische stabs a blade through Asar’s chest, cutting the heart in two. She leaves half in but removes the other half, placing it in her own chest. Asar’s mask falls to the floor, and Mische returns his own heart to his chest.

Asar regains his mortality and kisses Mische.

Nyaxia enters Morthryn and discovers what Mische and Asar have done with Alarus’s heart. When Asar refuses to let Nyaxia rip the heart from Mische’s chest, Nyaxia appears amused, informing them that Mische is too mortal to sustain the heart of an immortal for long. The truth of her words is proven by the spasms of pain that begin to seize Mische’s chest.

Mische collapses as the White Pantheon arrives to confront Nyaxia. Acaeja prevents violence between Nyaxia and Shiket, warning them of catastrophic loss. Acaeja claims that the House of Night and the newly arisen House of Death have pledged themselves to her, granting them her protection against the gods. Shiket is unwilling to accept this and promises a future war against the vampires.

Acaeja visits Asar and Mische. Acaeja gifts Mische with the strength to possess her portion of divinity and orders them to recover, rebuild, and prepare themselves for war.

Vincent visits Mische one last time. When she asks what he plans to do now, he expresses his belief that it would be selfish to seek out Oraya’s mother, who deserves peace with her family. He offers to lead a future army of the dead should Mische ever need his aid. Vincent then expresses admiration for Oraya and hands Mische a handwritten note that he hopes she’ll be able to deliver to Oraya in the land of the living.

Mische confronts Asar about leaving her his own version of a mask, an eye, and a heart in the underworld; these allowed her to access his power and cut out Alarus’s heart. Though he wanted her to sacrifice him, she admits that he was a sacrifice that she refused to make. The former warden of Morthryn, Esme, finds them and agrees to help them rebuild.

Weeks pass, and new borders are constructed between the House of Shadow and the House of Death. The House of Shadow is not pleased to share its territory with the newest house and shows this by murdering House of Death guards and sending their bodies back to Mische and Asar.

Raihn, Oraya, and Vale—who has recently been rescued from his captivity at the hands of Shadowborn spies during his travels to retrieve the god’s blood—visit Morthryn. Mische and Asar begin to strategize with the House of Night, preparing for the upcoming war. Afterward, Mische gives Raihn a tour of Morthryn, which has begun to repair itself. In privacy, Mische offers Oraya the letter from Vincent, which she hopes offers her the closure that she’s needed since his death.

Mische and Asar walk through the Descent together. He urges Mische to search for Saescha, who eventually visits Mische. She looks like she did in life, not like the hateful Sentinel she became, and regards Mische with a mix of emotions (though affection is at the forefront). Saescha smiles at Mische, clearly at peace.

After Saescha drifts away, Asar leads Mische to the poppy field where he has prepared the traditional Vathysian wedding ceremony for them. They complete the ritual, which resembles a necromancy spell in its structure, and are officially wed.

Septimus of the Bloodborn serves Nyaxia dutifully alongside Egrette of the Shadowborn as they prepare for war. However, he privately plots to bring about the downfall of the goddess after gaining her trust. Ten years pass in which Septimus bides his time, serving Nyaxia in the war against humans. By this point, the curse of bloodlust—which causes loss of reason and death in its final stages—that afflicts all Bloodborn vampires has begun to affect Septimus. Yet the time is near, and the culmination of his carefully laid plans resides amongst the pitiful scraps of the human nations, where a desperate mortal possesses a sword gifted by Shiket that Septimus needs.