In a flashback, The Darkling, i.e., Aleksander, arrives home where Luda, his Healer, waits for him. They talk about the King's hunt for Grisha.
Aleksander and Luda go inside and start packing. A group of soldiers surrounds the hut and demand Aleksander. He walks outside, and one of the soldiers shoots him with an arrow. However, Luda, who is secretly watching from inside, heals him. Aleksander tries to make peace with the soldiers, but they keep shooting at him.
One of the soldiers finds Luda and drags her outside. The soldiers bind both Aleksander and Luda, but one of them fatally stabs Luda. Aleksander begins to sob, but his grief motivates him to break through his binds and kill all the soldiers with the Cut.
Aleksander brings Luda to the Grisha sanctuary, hoping a Healer can save her, but there are no Healers there. Then, he goes to see Baghra, and they argue about the dire circumstances for Grisha. Baghra suggests Aleksander go into hiding until there is a new King, but he wants to do something about the Grisha the crown is persecuting now. He suggests using merzost, unnatural magic, but Baghra refuses. Baghra and Aleksander are descendants of the Morozova bloodline.
Aleksander disobeys Baghra and goes to the archives, where he finds Morozova's journals. He forms merzost.
The King's soldiers surround the Grisha sanctuary. Aleksander approaches the army and uses merzost to turn the King's army into volcra and establish the Fold. Then, he escapes with his mother.
In the present, The Darkling and his men near Alina.
In a flashback, The Darkling, then, Aleksander, arrives home to Luda, making sure she is okay. They talk about Grisha and the Grisha hunters.
Kaz, Inej, and Jesper gather everything they have left. Inej cannot travel yet because of her injury, but when she can, Kaz wants to return to Ketterdam. Kaz leaves the barn, and Inej tells Jesper she cannot return to Ketterdam because of Heleen.
Mal and Alina cuddle while waiting for the Stag. Mal hears the Stag, so they move toward it. Once they see the Stag, Mal helps Alina with her aim, but at the last second, she decides to see if there is another way to gain the Stag as an amplifier. Alina approaches the Stag and gently touches it. She summons a bubble of light, but it disappears when one of Kirigan's men suddenly shoots the Stag.
Mal fires back with the gun, but someone shoots him in the back with an arrow. A Heartrender takes control of Mal's heart, which prompts Alina to use her power to save Mal. She rushes toward him and pulls the arrow from his back.
Suddenly, the forest darkens, and Kirigan appears, ready to kill the Stag. Alina defends the Stag with another bubble of light. Kirigan strikes a deal with Alina -- if she gives up the Stag, his Healer will save Mal. Alina reluctantly agrees and lets go of her light, rushing toward Mal.
Once Alina reaches Mal, Kirigan's men pull them apart right before Kirigan slaughters the Stag. He tells David to get the Stag's antlers and tells his Healer to save Mal.
Kaz sits by the fire as Inej approaches. He realizes that she wants to leave. Inej gives Kaz his cane, which Jesper fixed. Kaz does not say anything, so Inej prepares to leave, but he stops her by saying that she was right about Alina. Inej joins Kaz by the fire, and she asks him about his faith. Kaz believes in the Crows, and he gives Inej a heartfelt speech. Then, Kaz promises Inej that she will not go back to the Menagerie.
David prepares the collar made from the Stag's antlers for Alina. Alina tries fighting back, but Kirigan subtly threatens Alina with Mal's life. Kirigan manages to quell Alina's worries for the time being so that David can place the collar on Alina. Then, David places a token on Kirigan's hand and forges a connection between The Darkling and Alina's power. After it is over, Kirigan tests out Alina's power. Alina tries fighting back, but Kirigan now controls her power.
Kaz, Inej, and Jesper hide as they wait for the people around the Conductor's train car to leave. They talk about the upcoming trip through the Fold. However, the train explodes.
Ivan and Alina arrive at an Army camp. As he escorts her to a tent, she sees Mal and tries to get to him, to no avail.
Inside the tent, Alina takes off her shawl and looks at her collar through the mirror. Genya arrives, and Alina hugs her in relief. Alina insists on telling the King about Kirigan, but Genya tells Alina that the King is ill. Alina realizes that Genya has been a spy for Kirigan all along. They argue about it until Genya tells Alina that the King abused her. Genya storms out.
Kaz, Inej, and Jesper talk about how they will cross the Fold. Kaz mentions sneaking onto The Darkling's skiff, where Alina will be. He plans to kidnap Alina and take her to Ketterdam, but he promises Inej that she does not have to join him and Jesper. Jesper realizes that people will recognize them on the skiff, so Kaz suggests disguising themselves as Zemeni guards.
Kirigan visits Mal, who he had locked up earlier. Mal threatens Kirigan. They talk about Alina's romantic feelings before Kirigan leaves.
Kaz, Inej, and Jesper knock out three people and steal their identities.
Mal tries to break free of his chains until he sees a goat. He realizes the goat has the key to unlock his cuffs, so he coaxes the goat toward him with food. Once Mal feeds the goat, he manages to unlock the chains.
The next morning, Kirigan visits Alina. Alina angrily confronts him about his past, and they have a heated, emotional conversation before Kirigan storms off.
Ivan catches up to Kirigan and informs him that Mal escaped. Kirigan orders Ivan not to hurt Mal unless he approaches Alina.
Kaz, Inej, and Jesper arrive at the docks and sign in with their false papers. They watch Alina and Kirigan leave a tent before climbing aboard.
Kirigan lies to Alina about Mal's situation as they get on the skiff. Mal hides under the deck.
The skiff sets sail into the Fold.