Taking place two months after the second film...
Anna, Queen of Arendelle, has been tirelessly preparing for the Polar Night's Celebration that is held every year to welcome the time when the sun doesn't rise in the Polar Circle. She has been working so hard, her fiancé Kristoff suggests she take a night off to visit her sister Elsa, the Snow Queen. Anna loves the idea. Accompanied by Kristoff, Sven, and Olaf, Anna reunites with Elsa in the Enchanted Forest.
After telling spooky stories around the campfire, Olaf swears that one of the creatures of their tales has come to life! Who else is responsible for the sudden onset of storms and the earlier than normal darkening of the skies? Why else is everyone starting to become so forgetful? Anna and Elsa join forces to determine what is going on. Together they recall Kristoff's terrifying tale about a princess who turned into a draugr—an undead creature that steals memories in an effort to make others forget the misdeeds it committed when it was alive.
Is it possible that Kristoff inadvertently unearthed memories of a draugr, and thus unleashed the monster upon Arendelle? Anna and Elsa must uncover the real story behind the tale before everyone in Arendelle forgets who they are and the whole kingdom is cast into darkness forever...
This novel contains examples of:
- Ascended to a Higher Plane of Existence: After the truth about Ingr and Sissel is revealed, Sissel sheds her decaying undead Draugar body and becomes a spirit before presumably going to the afterlife.
- Authority in Name Only: Elsa is still called Queen Elsa/Your Majesty by the people of Arendelle and people of other countries address Anna and Elsa as the Queens of Arendelle as if they are joint rulers. She is also called the Snow Queen, even though the only one who actually has the crown is Anna and Elsa spends most of her time in the Enchanted Forest. Elsa is officially the protector of Ahtohallan's memories.
- Body Horror: The Draugar's form is very unsettling with signs of decay all on its body.
- Both Sides Have a Point: Ingr, being a scientist with a fascination with the environment, automatically realized that Runeard's dam project would actually weaken the Northuldra's water flow and cause environmental devastation to the forest. This in turn would also affect other countries like Vesterland by depleting them of animals to hunt for food. Sissel, however, was initially reluctant to oppose Runeard since Arendelle is a very important partner for them, especially since their ports are the epicenter for trade. Though eventually the sisters decide to stand up to Runeard and force him to abandon the project together. And then Sissel dies...
- Clear Their Name: This turns out to be the Draugar's true motivation. She wants to clear her sister's name, which she does by erasing everyone’s memories so that they believe the truth when Elsa and Anna tell them.
- Continuity Nod: The book has a lot of shout-outs to other spin-off Frozen material.
- Forest of Shadows:
- Sorenson appears when the sisters go to him for help. They recount he was useful last time the kingdom was cursed, referencing the plot of the book.
- Also appearing are Ada and Tuva Diaz and the secret room in the library is mentioned.
- Ahtohallan is called the mother of the spirits, like in Dangerous Secrets.
- Anna mentions making a new clock to give to the queen of Chatho when she visits next month.
- Mari, King Jonas and Vesterland appear, the sisters having met them in Breaking Boundaries, and the Draugar used to be a Vesterland princess, Jonas’ cousin and he inherited the throne after her death and her sister's exile.
- The waffle brothers also appear; they are characters from a comic story "Just When You Weren’t Looking" in the official Frozen magazine.
- Elsa learned about her grandmother Queen Rita from Ahtohallan as well as seeing Agnarr and Iduna growing up, as shown in Dangerous Secrets.
- The village of Harmon is mentioned, a relevant location in the book Conceal, Don't Feel: A Twisted Tale. Due to the novel's alternate timeline, Anna was adopted by a couple of bakers and grew up in Harmon with no memory of her past life in Arendelle at all.
- In Forest of Shadows, Anna's horse's name is Havski. And in Dangerous Secrets, the horse Iduna gets from the farmer is named Havski, though she does end up calling the horse Kiekk a few lines later. In ''Polar Nights," the horse is again named is Havski.
- Forest of Shadows:
- Continuity Snarl:
- Anna and Kristoff are celebrating their sixth "Choco-versary" as in the anniversary of the first time they shared chocolate together, except that they only met three years ago.
- Kristoff is said to have blue eyes, but in canon they are brown.
- Elsa and Anna recount that Sorensen was useful last time Arendelle was cursed. This is supposed to be a reference to Forest of Shadows, but chronologically the last time Arendelle was cursed should have been in Frozen II when the spirits attacked the kingdom. Unless they didn’t consider that a curse so to speak.
- Foreshadowing: While checking out the spot where Ingr supposedly pushed Sissel into the river, Elsa loses her balance and falls into it herself. She would have drowned due to the current (and the Draugar halting her powers) had Anna not saved her. This is how Sissel actually died.
- In the beginning, after hearing how Runeard persecuted Ingr for murdering Sissel, Elsa and Anna think how unusual it is to hear that their grandfather did something good. Turns out at the end Runeard framed her.
- Frame-Up: Ingr didn't kill Sissel, she was pushed into the river by a flash flood and Ingr was unable to save her. But Runeard didn't want Ingr interfering with his plans against the Northuldra so he forced the one witness to lie and since then, Ingr has been painted as a Sibling Murderer who was jealous of her older sister and wanted the crown. This gets cleared up 50 years later at the end of the story by Elsa, Anna and her undead sister.
- The Good Queen: Queen Rita helped Ingr escape after Runeard got her sentenced.
- Green-Eyed Monster: Ingr reportedly killed her sister Sissel by pushing her into a rambunctious river because she wanted the throne. That's a lie, the sisters were very close, Sissel fell in by accident and Runeard placed the blame on her so he could get support to build his dam.
- Hate Sink: Once again, King Runeard. After Ingr accidentally drowned in the river while visiting Arendelle, Runeard forced the only witness to claim Ingr pushed her so he could get her arrested and coerce the next rulers of Vesterland into supporting his construction of the dam to weaken the Northuldra.
- Irony: Elsa, the one who gave up being queen to live in the Enchanted Forest, finds Oskar Ander’s reports on soil quality extremely boring while Anna finds them interesting.
- Knight Templar Big Brother: Sissel comes back from the dead as a Draugar, curses all of Arendelle with amnesia and hunts down Anna and Elsa to clear her sister's name after fifty years.
- Laser-Guided Amnesia: The Draugar has the ability to steal people's memories. Elsa is less affected (still enough to affect her ability to pull memories from Ahtohallan) than other people possibly due to her being a spirit. Anna experiences more forgetfulness than Elsa, but still remembers important things. Olaf, being a sentient snowman with no human brain or memories, isn't affected at all.
- Mirror Character: The Vesterland princesses (Ingr and Sissel) are like Anna and Elsa. Two sisters with Sissel being occupied with her people's safety (like Anna) and Ingr focusing on the environmental effects (like Elsa). Except that Sissel was the older one and future queen while Ingr was the younger. At first it seems like they are a foil to each other, with Ingr and Sissel hating each other and Ingr killing Sissel for the crown while Elsa willing gave hers to Anna, but that was actually a lie told by Runeard to prevent her from standing in the way of his plan to weaken the Northuldra.
- Misplaced Retribution: Anna at first thinks that the Draugar is after her because she is taking out her fury of having been killed by her own younger sister in an attempt to usurp the crown and Anna herself is the youngest sister who "took" the crown from Elsa. Turns out that the Draugar was just trying to go to her for help.
- Non-Malicious Monster: The Drauger is stealing people's memories but that's because it's actually Sissel and it's so that no one remembers the lies about her sister that Runeard told Arendelle, and chasing Anna and Elsa because she wants to show her how she really died. It is still causing a terrible storm and casting darkness over Arendelle but she seems to have no control over that.
- Ominous Clouds: The storm the Draugar brings to Arendelle blocks out the sky with black clouds.
- Our Zombies Are Different: A draugar is a simple minded undead creature out to right a wrong done to them in life and “wake up” when the deed is mentioned. They also have supernatural powers like causing storms, covering the land in darkness, erasing memories, teleportation, casting curses to sap people of their powers and super strength.
- Offscreen Teleportation: The draugar appears and disappears in the blink of an eye.
- Perpetual Storm: The Draugar brings an endless storm to Arendelle.
- Poor Communication Kills: The Draugar who's actually Sissel can only say two words "sister" and "mine". So when she tries going to Anna and Elsa for help, they think she is attacking them.
- The Reveal: The book answers a few questions fans have asked since the sequel.
- Elsa and Anna have charades night every Friday and they write to each other every day.
- Elsa is still considered a queen of Arendelle along side Anna but her official position in the Enchanted Forest is keeper of memories. She is also known as the Snow Queen.
- Ahtohallan is the spirit of memories which is embodied in the glacier. She also "talks" to Elsa by showing her visions of her mother.
- Elsa couldn’t have taken Anna to Ahtohallan in Frozen 2 because 1) The Nokk wouldn't have let her and the Dark Sea is impossible without the water spirit and 2) Only Elsa can access Ahtohallan anyways.
- Once freed from the enchanted forest the Northuldra started migrating north for the winter. Which explains their absence in most post-Frozen 2 works.
- Superpower Lottery: The Draugar causes storms, can steal people's memories, is strong enough to break through solid ice, seems to have the ability to teleport, can cast curses on other people to weaken them and at one point even absorbs and mimics Elsa’s ice powers.
- Took a Level in Badass: Thanks to her studying with the spirits, Elsa can now summon memories from her own mind with the use of her magic.
- The Wrongful Heir to the Throne: Played with, Anna remarks Elsa was a great queen but it’s established that Elsa always felt that Arendelle was a prison to her and she was never free to fully use or experiment with her powers and feels more comfortable in wide open spaces (like the forest). She is over this but enjoys having the best of both worlds being able to learn about her magic while still being allowed to use her old room in Arendelle castle once in a while. Anna also has more interest in listening to meetings, which Elsa found mind numbing.
- The Worf Effect: Draugars not only have the ability to steal people's memories Elsa even has trouble using Ahtohallan thanks to it but can also place curses on people to steal or suppress their strength which even works on Elsa's powers.
