Dianna and Liam flee through the crumbling catacombs while Tobias’s undead pursue them. Liam realizes the crown embedded in Tobias’s skull marks Tobias as a King of Yejedin, one of four beings older than Liam, and says this explains Tobias’s power, Kaden’s nature, and why Kaden is so determined to reclaim Dianna. Dianna rejects the idea that she is Kaden’s queen, but Liam insists they must return to the tomb chamber because Azrael’s Book is still inside.

Liam attacks Tobias to distract him while Dianna fights through the undead and searches for Victoria’s tomb. The battle devastates the mausoleum: Liam and Tobias hurl each other through stone, coffins are torn apart, and more corpses pour in. Dianna finds signs of the tomb but is repeatedly overwhelmed, stabbed, and forced to keep fighting with weapons and fire until exhaustion and injury leave her unable to keep pace with the endless dead.

Recognizing that Tobias’s army and the collapsing cavern may trap them both, Dianna urges Liam to abandon her, get the book, and save Gabby as promised. Liam refuses to leave Dianna and says he cannot use his most destructive weapon in the cramped chamber because it would kill her too. Dianna decides Liam will never choose the book over her unless she forces his hand.

Dianna creates a false bundle of bones wrapped in cloth to make Tobias believe she has Azrael’s Book, then runs from the chamber. Tobias and the undead pursue her through the tunnels, and although Dianna uses fire and climbs to an upper level, Tobias tears through the stone, catches her, drains her strength by biting her throat, and discovers the ruse. He drags Dianna back to the tomb chamber as bait.

Tobias holds Dianna hostage with his claws inside her chest, threatening to rip out her heart if Liam moves. Tobias taunts Liam for hesitating and suggests Liam could kill both Ig’Morruthens and take the book, but Liam instead offers to trade Azrael’s Book for Dianna’s life. Liam opens the sealed coffin and retrieves the book, horrifying Dianna because she knows Tobias will not truly release her and that Kaden cannot be allowed to have it.

When Dianna sees that Liam is willing to surrender the book to save her, she reminds him of his promise to care for Gabby. Liam reacts with fear, understanding what Dianna intends. Before Liam can stop her, Dianna uses her remaining strength to pull Tobias’s hand from her chest, ripping out her own heart with it.