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Hilda and the Time Worm is the fourth volume in the Hilda Tie-In Series of children's novels, based on the Hilda animated series. The book was published on Nov 17, 2020[1]


We rejoin our favorite blue-haired heroine Hilda to find her cooking up adventure with the Sparrow Scouts, thwarting mischievous Yule Lads, and battling mechanical bell-ringers. Can Hilda and her friends help the city of Trolberg escape the hungry Gryla and her light-fingered crew? There is no shortage of unexpected twists, turns and new friends in this fourth installment of the Hilda fiction series.


The Trolberg Winter Festival is approaching, and Hilda, Frida and David are selling broth for the Sparrow Scouts at the Trolberg Market.  Hilda hopes to use her share of the tips to buy her mother a snow globe for the festival. Trevor and his friends attack their stand with snowballs. Before Hilda and friends can fight back, Erik Ahlberg and Gerda Gustav of the Trolberg Safety patrol show up, scaring away the bullies. They tell Hilda she won the first ASPECT (Annual Safety Patrol Essay Contest Trophy), and her price is being allowed to go on an inspection of the Trol Defences with them.

Thus, the following day, Hilda is picked up by Erik and Gerda with a zeppelin. Alfur secretly comes along for the ride. During the patrol, Hilda quickly grows annoyed with Erik. First he misinterprets her essay to make it look like a troll tried to harm Hilda while it only wanted her to remove the bell from it’s nose, and during the ride he reveals that he plans to have mechanical bellringers installed in all bell towers in order to ring them every 15 minutes so all trolls in the area will be forced to evacuate. Hilda knows that the trolls are more likely to  retaliate, but Ahlberg doesn’t care; he is willing to wage war with them for the glory.

During the ride, Hilda also spots a wooden farmhouse that she never saw before. Later, she and Alfur notice a large, hunchbacked creature walking through the valley.  After the inspection is over, Hilda tells her friends about Erik’s plan, and her discovery. They investigate the strange farmhouse, and inside they meet the Yule Lads, who are in Trolberg to look for naughty children. Hilda quickly gets along with their leader, Kertasnikir, and invites them to come with them to the market that night, which they do. There, she finds out that  Kertasnikir is not above being naughty himself; he steals candy from a stand, and accidentally causes panic by shouting “Troll” when trying to solve a riddle Hilda gave him (about Trevor being a naughty kid).  In response to his false alarm, the bells begin to ring, which startle a group of Woff that where flying over the city, and they crash onto the ground. Hilda helps a few of them get back up. The last one, a big Woff, accidentally drags Hilda with him when he flies away. Hilda jumps off the Woff, and is fortunately saved by the bell keeper from the tower in Gorrill Gardens. After the rescue, they talk a bit, and Hilda learns from the man that the mechanical bellringers Erik mentioned will be activated the next day. The bellkeeper hates them since they will put him out of a job, but when Hilda suggests they sabotage them he deems this impossible.

When she arrives home, Hilda briefly sees her downstairs neighbor Mr. Ostenfeld collecting his mail, a large stack of magazines, but he is not interested in talking with her. Once in her apartment, Hilda gets a visit from Bartell, the leader of the Lost Clan. They too are bothered by the new bell ringing, and want Hilda to help them stop it. When Hilda realizes her mom has a blueprint of the new mechanical bellringers because she has been hired as graphic designer for the project, she hatches a plan to sabotage the system. She also ropes in David, Frida and Tontu to help.  The following day, while Ahlberg is giving his speech at the switching-on ceremony, Bartel and the lost clan attack the central belltower and distract the guards. Tontu then uses nowhere space to help Frida, Hilda and Twig get into the central belltower, where they hope to turn off all the bellringers by clipping a cable. It works, but it turns out there is a backup system in place. Frida quickly figures out that the master wire of this backup system is in the top of the tower, so Hilda hurries to sabotage that too. She finds the door to the control room locked, but to her surprise the bellkeeper shows up and lets her in. The two of them are unable to find the master wire before Ahlberg activates the bellringers. In a desperate attempt, Hilda turns the volume of the bells to maximum, so the system overloads and shorts out. The largest bell even breaks off it’s hinges and falls on top of Erik Ahlberg.

One danger is over, but when Hilda and the bellkeeper enjoy the returned silence, Hilda once more spots the strange hunchbacked creature she saw earlier from the airship. It is getting closer to Trolberg. When Hilda leaves the tower, she runs into her mom, and quickly lies about where she has been. Unfortunately. Johanna knows what Hilda has done since she saw Hilda in the tower, and this lie angers her further. She grounds Hilda, which means Hilda won’t be able to attend the Winter Festival that evening. That evening, as Hilda is in her room, she is visited by one of the Yule Lads; Gluggagaegir. When she tells Gluggagaegir why she is locked in her room, Hilda, who knows that her actions that day saved Trolberg from a war with trolls, claims her mom is naughty for punishing her for doing something good. Gluggagaegir is surprised to hear that adults can be naughty too. He runs off to tell the other Yule Lads this news.

No sooner is he gone, or Hilda spots Mr. Ostenfeld with one of the magazines he ordered. She sees how he opens it, and suddenly disappears for a few seconds. Curious, Hilda uses the drainpipe to climb onto Mr. Ostenfeld’s balcony, where she discovers he ordered multiple copies of the same magazine. She opens one, and is promptly send back in time to December 1947. In her panic, she drops the magazine, and is transported back to the present, where Mr. Ostenfeld catches her snooping around. To escape him, Hilda uses another magazine to go to 1947 again. Ostenfeld follows her. In the past, Hilda learns that on this night in 1947 Mr. Ostenfeld met a young girl and had a wonderful night with her, but was too shy to ask her for her name or address, and thus never saw her again afterwards. He considers it his biggest regret, and ever since he accidentally discovered that copies of the magazine he was reading that night can transport him back to this night, he has been using them to relive the night over and over. Each copy only works once, and every trip back results in another Ostenfeld being here in 1947 (there are 8 of them already).

Hilda is moved by this story, and asks Ostenfeld why he only goes back to observe instead of trying to change the past and fix his regret. Ostenfeld is afraid of the consequences. Hilda grabs the last magazine and decides to do it herself. She goes back to 1947 again and convinces the younger Ostenfeld to follow the girl after she leaves the club. It works, and she creates a new timeline in which Mr. Ostenfeld and the girl, whose name turns out to be Matilda, are together. This however attracts a Time Worm; a creature whose job it is to tidy up the timeline. It begins to devour the various copies of Mr. Ostenfeld, and also targets Hilda. Hilda tries to escape the creature by first using the magazine to return to the present, and then, when the worm follows her through time, by using the worm’s own time portals. She briefly visits ancient Trolberg, where she witnesses Edmund Ahlberg and his army fighting against trolls. Eventually, she ends up back in the present, where she meets the Mr. Ostenfeld and Matilda from the new timeline, in which they are happily married. There is also one last Ostenfeld from the original timeline, who managed to escape the worm and informed his counterpart from the new timeline about what has happened. Since they know this new timeline is wrong, in spite of their own happiness, Matilda and her husband sacrifice themselves to the Time Worm to restore the timeline and save Hilda and the original Ostenfeld. Now that he has seen all of this, Mr. Ostenfeld decides to stop time traveling and just cherish the memories he has of him and Matilda.  He gives Hilda the last magazine, and some money as thanks for her help.

While Hilda has her adventure with the time worm, Frida and David are still on the Winter Festival Market selling broth. They spot Trevor, who is up to no good again, and Johanna, whom they question about Hilda’s absence. Then the Yule Lads appear and abduct both Trevor and Johanna. At her home, Hilda is back in her room, having decided to just sit out her punishment after her narrow escape from the time worm. She still has the magazine she used to time travel, and when she reads it, she finds an article about the legend of the Yule Lads. From the article, she discovers the Yule Lads want naughty people in order to feed them to the ogress Gryla. Hilda realizes she endangered Trevor and her mom by telling the Yule Lads that they are naughty, and with Tontu’s help she hurries to the Sonstansil Tree, and confronts the Yule Lads with her discovery. To save her mom and Trevor, but also save the Yule Lads from Gryla’s wrath, Hilda convinces them to give Gryla the broth she, Frida and David had been selling. Frida is reluctant to give up her secret recipe, but eventually relents.

As Gryla enters Trolberg, Hilda recognizes her as the creature she saw from the zeppelin and from the Belltower. Gryla fortunately accepts the broth and leaves. Once she is gone, the big glow starts. Johanna and Trevor are returned to their home, and Hilda hurries home too before he mom wakes up and notices her gone. She stops on the way however to use the money she got from Mr. Ostenfeld to buy the snow globe. Once Johanna wakes up at her home, and thinks the adventure with the Yule Lads was just a nightmare, Hilda gives her the snowglobe. She may still be grounded for another 2 weeks, but at least she and her mom have reconciled.

Featured Characters



Yule Lads





Mentioned characters

The following characters are mentioned, but make no appearance:


The book combines characters and plot elements from the episodes "Chapter 1: The Troll Circle" (only the first half of the episode), "Chapter 6: The Old Bells of Trolberg", "Chapter 8: The Fifty Year Night", and  "Chapter 10: The Yule Lads". Hilda’s adventure from "Chapter 10: The Storm" is briefly mentioned but not shown in detail.

Like the previous book, the novel rearranges the order in which these events happen compared to the animated series, so the events make up a single story rather than individual adventures. It also takes several other liberties with the episodes it adapts. Included:

  • For "Chapter 1: The Troll Circle", the book only adapts the part of Hilda, Erik and Gerda going on patrol with the zeppelin.
  • The novel claims the broth that Hilda, Frida and David sell is from Frida’s great-great-grandmothers secret recipe. The animated series never states where the recipe came from.
  • In the series, Erik and Gerda came to Hilda’s house to tell her about her winning Essay.
  • In the series, Kertasnikir liked to steal candles, not candy.
  • In the series, David is the one that comes up with the name Operation Deerfox Thunder Team for the plan to sabotage the bells.
  • In the series, Frida has begun her witchcraft studies at the time she and Hilda sabotage the bells, and uses magic to find the right cable. Here, they have to search for it manually.
  • In the series, Hilda is grounded because of her adventure with the Kraken (which is adapted into the next book), and Johanna never finds out Hilda had anything to do with sabotaging the mechanical bellringers.
  • In the series, the magazine that Peter Ostenfeld uses to time travel is named Trolberg Digest, and no specific year is given. Here, it is the December 1947 edition of Elan Magazine.
  • According to Mr. Ostenfeld, the flat that he and Hilda live in was once the jazz club where he met Matilda in 1947. Hence why he bought an apartment there when the club was shut down and converted to apartments. In the animated series, the flat and club are separate buildings.
  • The book never explains how the time-travel magazines work. In the series, it was because Matilda enchanted the original magazine that Peter Ostenfeld had with him the night they met.
  • While Matilda appears in this book, it is not until the next book that it is revealed she is a witch.
  • In the book, Alfur identifies the Time Worm as such. In the series, he was as clueless as Hilda about what the creature is, until Matilda told them both.
  • In the series, the effects of the time travel are undone by destroying the original magazine that Matilda enchanted. Once the timeline is restored, Hilda is the only one who remembers the adventure. Here, Mr. Ostenfeld also retains his memories and somehow even a photoalbum of snapshots from the now erased timeline in which he and Matilda where together.
  • In the series, Hilda learns about the Yule Lad’s true intentions from a book her mother owned instead of the magazine.
  • Trevor’s mom is also targeted by the Yule Lads in the series. Here, she is never seen or mentioned.


ve Hilda books
Graphic Novels HildafolkHilda and the Midnight GiantHilda and the Bird ParadeHilda and the Black HoundHilda and the Stone ForestHilda and the Mountain KingHilda: The Wilderness Stories
Hilda Tie-In Series Hilda and the Hidden PeopleHilda and the Great ParadeHilda and the Nowhere SpaceHilda and the Time WormHilda and the Ghost ShipHilda and the White Woff
Other books Hilda's Sparrow Scout Badge GuideHilda's Book of Beasts and Spirits