The following version of the book was used to create this study guide: Black, Holly. The Stolen Heir: A Novel of Elfhame. Hatchette Book Group, New York, NY 10104. 2023. Kindle AZW file.

Wren was ripped from her adoptive family at age nine and taken to the faerie land of Elfhame where she was brutalized by Nore and Jarel who claimed to be her parents. After escaping, Wren returned to the mortal world and lived a feral life in the woods near the home of her adoptive family. As she watches her sister Bex, who is now in college, Wren wonders what her life would have been without Nore and Jarel's interference. One night, Wren encounters the storm hag named Bogdana. Bogdana might have captured her except for the intervention of Oak, the prince and heir-apparent of Elfhame. Oak is traveling with a single guard, Tiernan. They tell Wren that Nore has gained a new piece of magic which allows her to create life from nothing. Tiernan berates Wren for not taking advantage of the power she was given to control Nore. Wren was just a child when that happened, and Oak understands that she did not know how to use that power. Wren agrees to help Oak stop Nore, and they set out on their quest. They are soon caught up in the dangers of their journey, including a battle with some of Nore's creatures that are made out of wood.

The group which is made of Oak includes Tiernan, Wren, and a faerie named Hyacinthe. Hyacinthe has been caught in a terrible curse that is slowly turning him into a falcon. A kelpie named Jack joins the group. They enter the Court of Moths – the southernmost court in Elfhame. Since Hyacinthe is technically a prisoner, Queen Annet of the Court of Moths demands that he remain in her prison. Wren worries that Annet will somehow manage to keep Hyacinthe when they leave. So, Wren sets out to release him. Wren is able to break the curse against Hyacinthe, earning his allegiance. Wren sends Hyacinthe to hide along with a couple of others being held prisoner by Annet. Jack helps, but he turns her in when he is caught. Wren explains that it was cruel to keep the three prisoners, but Annet is angry. When she threatens to hold them for ransom, Oak fights an ogre to secure their release.

Oak, Wren, and Tiernan then visit a Thistlewitch who tells them the story of a hag who made a deal with an ancient faerie queen named Mab. The hag gave Mab the power to create. In return, Mab was to raise the hag's daughter, Mellith, to be her heir. Mab tried to get out of he deal so that she could make Clovis, her own daughter, her heir. The hag set out to murder Clovis, but Mellith was killed instead. Wren immediately begins to wonder if Bogdana is the hag from the Thistlewitch's story. Nore is using a bone from Mab's body as a basis for her magic. Nore needs Mellith's heart in order to make her magic permanent. Oak spends a little time alone with the Thistlewitch before announcing that the heart is out of Nore's reach.

Wren and Oak make their way into Nore's castle. Wren has only to speak a command in order to control Nore, but Wren is bound before she can do so. Nore has Wren's tongue cut out. Wren is surprised that Hyacinthe is present, meaning he has put himself in a position to help Wren if she needs him. He leaves a key so that she can escape her cell, but she chooses to search for a way to defeat Nore instead of running away. Wren finds a piece of Mab's bone and a magic leaf that heal her tongue. She feels a terrible splitting inside her and soon realizes that this is her magic power breaking free. Her tongue regrows, and she takes control of Nore. She and Oak make a plan to take control of Nore's entire army, including a group of trolls. The plan goes awry when Wren learns that Bogdana was the hag who made the deal with Mab. Additionally, Bogdana used Mellith's heart when she created Wren. Wren has the power of an unraveler, a stronger power than anyone else present. She unintentionally kills Nore in a moment of fury. She takes control of everything and everyone. She pledges to remove a curse plaguing the trolls. This prompts the allegiance of the troll king. Feeling betrayed that Oak knew the truth and kept it from her, Wren puts him in prison. As the novel comes to an end, Oak is screaming Wren's name, pleading for the chance to explain.