Asar brings himself and Mische to the House of Night. The spira nearly kills Mische, her body unable to handle the transportation of the gods, but Raihn and Oraya aid Asar in stabilizing her.

When Mische wakes, Raihn and Oraya plead for her to tell them everything, but she refuses to endanger them with the truth. They’ve been holding Asar prisoner since his arrival but allow him to visit Mische at her request.

Though he can easily break out, Asar waits patiently in his prison cell. Meanwhile, the voices from the mask and eye speak in Asar’s mind, intermingling his thoughts with Alarus’s. His memories of emerging from the spira are hazy due to the mask’s power, but he remembers using the power of the mask and eye to heal Mische.

He is eventually retrieved by Jesmine, the Nightborn head of war, and brought to Mische, who looks more alive than she did before. When she sees the damage that the mask has done to Asar’s face, Mische warns him that the relics are dangerous. She reveals that when she looked at him while he was wearing the mask, she didn’t see him behind it. She reminds him of his promise not to sacrifice his mortality, but Asar asserts that his actions were the only way to escape the deadlands. When Asar instinctively grasps Mische’s hand, they realize that they no longer feel pain at their bare skin touching. Rather than analyze how this is possible, Asar kisses her.

Asar and Mische have sex. She cries at her ability to feel everything—to feel so alive. Afterward, Asar explains that the mask and eye pulled her closer to life when he healed her but that she’s not quite fully alive. Asar is clearly bothered by the unknowns of her condition, but Mische reminds him that she loves his mortality, even if it leaves him in the dark sometimes. She does not know that he already bargained his mortality away when he accepted this mission from Acaeja.

Mische tells Asar of her communications with Vincent, and they contact him through a mirror. Vincent appears fainter, as the underworld’s continued decay makes it more difficult for him to access Mische. Vincent hypothesizes that they’ll be able to find the heart if they use Alarus’s blood for an anchor spell. He tells them that the underground hallways in the Nightborn palace are hidden from the gods and would make an ideal location to conduct their spell.

Mische and Asar meet with Oraya and Raihn. Mische tells them about everything, including her death and the fact that she’s a wraith. Oraya and Raihn tell them that the kingdom has been experiencing earthquakes and that wraiths have been seeping into the House of Night’s lands, which sit on a weak point in the veil. Mische gets confirmation that Oraya and Raihn are refining the blood of Alarus in case they need to weaponize it in the coming war. They reveal that Nyaxia requested help from the Houses of Blood and Shadow in the war, but not from the House of Night. Raihn and Oraya offer their help in opening a door that will allow Asar and Mische to steal the heart and Asar to ascend to divinity.

A general for the House of Night, Vale, ventures to retrieve the blood while Asar and Mische begin constructing the ritual circle. Mische has a private conversation with Raihn in which he reveals how devastated he is to hear of what she has endured and expresses concern about her current state. After their heart-to-heart, Raihn good-naturedly teases Mische about her relationship with Asar.

As Oraya, Raihn, Asar, and Mische continue their research into spells to complete the ascension, Asar battles with the growing influence of the mask and eye. More and more often, he loses himself in their whispers. The only effective distraction is intimacy with Mische.

Oraya speaks to Mische about Vincent. She still mourns her father, and while she’s grateful that he’s guiding Mische, she mourns that she never got to experience that selfless kindness for herself. While Mische states that Oraya doesn’t need to forgive Vincent, she does note that Vincent cares for Oraya. They are interrupted by screams just before a nearby window shatters and a horrifying monster bursts through.

Asar is so lost in the research and the whispers of the mask and eye that he doesn’t notice the commotion around him until Luce bites at him. Asar encounters Raihn in a hallway as they both head upstairs; together, they enter the women’s room, where they discover a mutated souleater that has absorbed the corporeal bodies of its prey. Asar and Mische see Celie, the young girl they helped pass to the underworld, among the screaming victims entwined with the souleater’s body. Together, Mische and Asar draw the glyphs to open a door to the underworld and send the creature back through. The city of Sivrinaj is split in two from the fracturing of the underworld, causing dozens of deaths among the House of Night.

That night, Mische distracts Asar from their guilt over Celie’s undeserved fate by gifting him a cello she made for him. He teaches her to play a song, which she weaves with the magic of illusion. The illusions depict the future she wishes for them—Luce, a grand library, and Asar and Mische living happily together in a Morthryn restored as their home.

Oraya arrives in the dead of night to collect Mische and Asar, claiming that Vale has returned with the god’s blood.

When they enter Oraya and Raihn’s private meeting room, Asar recognizes “Vale” immediately as Gideon. Gideon has crafted a powerful Shadowborn illusion that fooled Oraya, Raihn, and even Mische.

Gideon reveals that when Asar tortured him for the glyphs needed to open the door to the mask, he hid a tracking glyph among them. This has allowed Gideon to know Asar’s every move. He has alerted the gods to their plans, drawing them to the House of Night. Gideon destroys the vial of god’s blood, sacrificing his life in the process.

Several Sentinels invade the palace and capture Mische before Asar can reach her.

The same Sentinel that’s been hunting Mische takes her to the Citadel of the Destined Dawn in Vostis. The city is filled with humans, many of whom are acolytes or aspiring acolytes of Shiket and Atroxus. Mische has a foreboding feeling that Nyaxia plans to strike the city while the other gods are distracted at the House of Night. She attempts to warn the Sentinel but is too late.

Asar leaves Raihn and Oraya to defend the House of Night while he dons the mask and eye and takes the spira in pursuit of Mische.

Nyaxia’s army of Bloodborn and Shadowborn vampires slaughters the humans of Vostis. Left alone with human acolytes as the Sentinel goes to battle, Mische compels a woman—Kyrene—to free her from her bonds. Though the other acolytes die in the carnage, Mische attempts to bring Kyrene to safety. However, when they reach the front doors, they find them locked from the outside. Before they can find an alternative escape, an explosion occurs, ripping Kyrene from Mische’s grasp and throwing Mische through a window.

The Sentinel who captured Mische attacks her, unwilling to let her escape. Their mask is cracked, revealing their face, and Mische recognizes her own sister, Saescha. However, there is no trace of humanity or compassion left in her sister. Before Saescha can kill her, Luce appears, knocking Saescha back. Another explosion forces them further apart.

Asar lands on the battlefield of Vostis, where he spots Mische in the distance, fighting on the beach to save the very humans who scorned her. Egrette intercepts Asar on the battlefield, offering him as a sacrifice to Nyaxia.

Asar confronts Nyaxia, correctly assuming that she possesses Alarus’s heart. She reveals that he left it to her shortly before his death and that she consumed it to become a goddess. Sensing her profound loneliness, Asar offers her a deal. In exchange for the heart and his ascension to divinity, he offers her his allegiance and support in destroying the White Pantheon. He also requests that she spare the remaining humans in Vostis and grant the House of Night mercy. Nyaxia accepts his bargain and rips out Asar’s heart, only to replace it with Alarus’s.

Asar becomes the God of Death. His humanity is a distant thing. Though the woman fighting on the shore looks familiar to him, he does not remember her. Nyaxia calls for an end to the battle, sparing the remaining humans. Meanwhile, the woman on shore pleads with the God of Death, calling him “Asar” and urging him to remember why he chose to ascend. He turns away.

Mische mourns the loss of Asar’s humanity and his broken promise to her as he and Nyaxia take the spira from Vostis. Luce throws herself through the portal after him. Mische is attacked by Saescha but only hugs her sister, watching over Saescha’s shoulder as a firebird rises from the distant burning forest.