Tiny, invisible people threaten Hilda's fun and adventurous life in the wilderness with her Mother and pet deer-fox, Twig.
Hilda and her pet deer-fox Twig are outside, jumping on rocks in a river next to a waterfall. She almost lost her sketchbook, but Twig fortunately catches it before it falls in the water. Hilda caught Twig in her arms, when suddenly a Water Spirit rises up under her and takes them to the other side of the river. They're climbing a mountain with a snow cloud following above her when they see a pack of Woffs flying accross the sky. After some more rock climbing.
Hilda takes out a sandwich and starts to eat it before she notices a big Troll rock. She tells Twig that Trolls don't usually come this far down the mountain, which makes her eager to sketch it. Twig sniffs the Troll rock, but his curiousness made him afraid of the creature. He bits and pulls on Hilda's skirt, wanting to run away. She calms him down, telling him that this Troll doesn't think about eating them right now, as long as it's daylight and just a rock. But once the sun gets down, they're doomed, hearing that makes Twig more scared. She gives Twig a bell and tells him to hang it on the nose of the Troll rock and once the Troll moves, it jingles. That tells them to run for their lifes. Twig does what she told him to and we see Hilda starting to sketch the Troll rock, sitting next to a rock herself.
As it's getting dark and Hilda sketched half of her sketchbook about the Troll rock in half a day, without finishing her sandwich in which she took only one bite from. Hilda is finally finished and happy with one of her sketches, but instead decides to draw one more sketch, while Twig sleeps on the ground next to her. Suddenly, the Troll rock moves as the Troll awakens. Hilda and Twig flee, but the Troll keeps following them all the way to their house. It's only there that Hilda realizes the Troll just wants to get rid of the bell on his nose, which he can't reach with his own hands. Hilda carefully removes it. In turn, the Troll picks her up, seemingly to eat her, but he returns her sketchbook to her.
Later that evening, the Wood Man pays a visit to Hilda's house to warm by the fire. After a knock on the door, Hilda finds a tiny envelope on the doorstep; the sixth she and her mom received that week. It's another notice telling them to move, or else their house will be destroyed. Hilda is unimpressed and writes a letter back to the mysterious sender. That night, while Hilda, Johanna and Twig are sleeping, and invisible creatures enters the house. They begin to talk to the humans trough the television, and wreck the living room. Hilda fights back with a broom, and manages to drive them off.
Johanna, scared by the attack, states they will move to Trolburg if another such thing happens. Not wanting to move, Hilda tries to seek contact with the invisible creatures to negotiate. She is visited in her bedroom by Alfur, and elf. He helps her fill out the proper paperwork so Hilda can see him and the other elves, thus discovering that her home is in the middle of an elf village (something she never knew). Alfur explains to Hilda that the new Prime Minister had promised to get rid of Hilda and her mom if he got elected, hence why the Elves have suddenly become hostile with the humans. Hilda wants to talk to this Prime Minister, so Alfur promises her to arrange a meeting with the mayor first. As Hilda returns home, she sees a giant the size of a mountain looking at her home.
The following day Hilda meets the mayor, who is very rude towards her. He refuses to help Hilda see the Prime Minister, until his pet cat Angelina decides to hide in Hilda's hair, causing the mayor to think Hilda took her hostage. With instructions from the mayor, Hilda and Alfur set out to find the Prime Minister. They come under attack from the Prime Minister's cavalry (Elves riding rabbits), but Twig scares them off.
When they find the prime minister, Hilda tries to reason with him, even promising to make compromises to limit the annoyance she and her mom unintentionally gave the elves. The Prime Minister however claims that he can't end the war against them either; only the king can. Disappointed, Hilda leaves. Alfur however promises to bring her to the king, even though this violates all protocols.