Hilda's essay about her close encounter with a troll wins her the chance to tag along with Trolberg's new head of the safety patrol, Erik Ahlberg.
A quest to uncover secret information about Ahlberg leads Hilda on a high-seas adventure with the Wood Man that lands them in a boatload of trouble.
After Hilda and Frida come across a magical portal at the library, they must team up with the librarian in a race against time to find a missing book.
David confronts his many fears when he stumbles into a ferocious battle during an overnight Sparrow Scouts camping trip with Hilda and Frida.
On a bird-watching expedition, Hilda, Frida and David run into meteorologist Victoria Van Gale, whose calm new life makes one of them very suspicious.
Chaos comes to Trolberg when the bell system begins to ring every hour, inspiring Hilda and friends to hatch an elaborate scheme to quiet the noise.
Hilda and Frida launch an in-depth investigation to prove the fire-breathing resident of Cauldron Island isn't responsible for a wave of boat attacks.
Hilda learns all too well that actions have consequences after she discovers a way to travel back in time - and decides to make a few changes.
After Hilda's deer-fox companion Twig leaves home and runs into the wilderness, Hilda and her mum set off on a search that stirs bittersweet memories.
On their way to Trolberg's Winter Festival, Hilda, Frida and David come across a group of odd little fellows who are on the hunt for naughty kids.
Hilda and pals gear up for a magical mission: to reverse an enchantment that's taken over the headquarters of the local snack food company, Jorts.
Desperate times call for desperate measures as Alfur faces questions from the Elf Kingdom over his exciting reports from Trolberg.
Hilda, her mum and Twig look for a way out of a mysterious forest full of trolls, while a worried David and Frida journey out of Trolberg to find them.
We rejoin our heroine for her latest adventure just as she awakes to find herself... in the body of a troll! Her mum is worried sick, and now has to deal with the strange creature that seems to have taken Hilda's place. Now, both of them are in a race to be reunited before Ahlberg and his safety patrol get the chance to use their new secret weapon to lay waste to the trolls, and Hilda along with them!