Jul i Valhal is primarily about two children named Jonas and Sofie, and their adventures with the Norse gods.
The story begins with Sofie (Laura Buhl) being told by her single mother, Tove (Ann Eleonora Jørgensen), that they have to move to Singapore by the end of December for her job, and for her new boss, Mr. Tong.
When they reach Ragnhild's house on a hill called "Loki's Hill", they find that the loft is being rented out to a woodsman named Asbjørn (Troels Lyby), who is also a single parent, and has two children named Jonas (Lukas Thorsteinsson) and Emma (Clara Bahamondes).
Sofie and Jonas become close friends very quickly, but Tove and Asbjørn have a lot of tension and animosity between each other because their personalities are opposites.
Tove has a great love of technology and business, while Asbjørn values nature and days of honest labour outdoors.
She accidentally kicks a small rock into the dolmen, and afterwards she hears strange bell-like metallic noises coming from within.
Ragnhild tells the children that it is because the legends say the old hill near the house is the place where the Norse god Loki is still chained.
That night, before she goes to bed, Sofie looks out a window and sees a yellow glow emanating from the top of Loki's Hill.
When Jonas comes home from school, he notices that Sofie has mud on her clothes, and knows that she was outside playing instead of healing indoors.
They gather together some goods to bring to Loki, including a razor, some men's underwear (both belonging to Asbjørn), and some scissors.
Loki's spell works, and Asbjørn promptly purchases a large television, and Jonas tells Sofie what he has done.
She tells the children that Fimbulwinter is the harbinger of Ragnarok, which she describes as the battle in which all humans, gods, and giants will die, but she adds, it won't come until Loki has been freed from his chains.
Back in Utgard, Thrym decides that he doesn't need Loki anymore, since he has the Fenris wolf, and the Fimbulwinter is well underway.
Loki decides that it is not worth it to fight his family anymore, begins to regret having started Ragnarok, and flees to Midgard.
But, since Hel was invited to the Yule celebrations this year (previously the other gods had excluded her because they considered her to be strange), she allowed Balder to come along with her, and Odin rejoices in seeing his son again.
Back at Ragnhild's house, Sofie does not enjoy her Christmas dinner, because she is constantly thinking about the move to Singapore.
They hear the taxicab arrive in the middle of dinner, so Sofie and Tove go outside, but the cabby is actually Loki in disguise.
There are 24 episodes to corresponding to days from 1 to 24 December: The series has many running gags that it employs, including: Following the success of the miniseries, a feature film was made as a sequel, called Guldhornene ("The Golden Horns").
The film is about Loki, Thor, Heimdall, and Idun in Midgard, trying to prevent two golden horns from falling into the wrong hands and causing the extinction of humans.
Since the gods do not know how to operate in the modern world full of technology, they employ the help of Sofie, Jonas, and Emma.