We get to know Selma, a nine-year-old orphan who lives in Oslo with her stern caretaker Ruth, and who most of all wants a family; in Snøfall, an isolated village in the arctic, we meet some of its inhabitants, like the reigning Santa Claus.
When Ruth unexpectedly inherits a bookshop, Selma is overjoyed. Ruth is however not as fond of the idea; Selma also befriends new neighbor and classmate Håkon, who believes in Santa Claus.
Julius hears from the Oracle and is told who the new Santa Apprentice is; Ruth wants to sell the bookshop; Julius tells the class about Darkness, a forbidden part of the garden; Ruth is told child care has found a new foster home for Selma.
Julius receives Selma's letter and wonders if she may be Albin's daughter, and thereby his granddaughter; Selma and Ruth have a huge fight about the bookshop.
Selma walks out in the arctic, looking for a light at the end of the tunnel; Ruth is back home, upset and thinking Selma has been sent to a new foster home without her being notified; Winter gets a huge surprise.
Julius is gone when Selma wakes up and is nowhere to be found; Selma also meets Pil, who persuades her to come to Santa school, but she gets a little overwhelmed; Håkon begins his mission to get Ruth to keep the bookshop.
Upon hearing that Selma might be the new apprentice, Winter panics and invites her to dinner to see if she knows anything about it; Ruth doesn't know what to do with Casper; Selma bonds with Pil while looking for Julius.
When Winter changes the annual Christmas party into a meeting for adults only, Selma and Pil decide to sneak in, so they can learn who the new apprentice is.
Winter places Julius's Santa hat outside the town for someone to find, so the people will falsely start to believe Julius really has retired; Ruth tries to find meaning in the letter that Selma sent her.
Winter tries to convince the people that Julius has really stepped down as Santa; the annual Snøfall snowball battle is here, and the kids are really excited.
After having a huge fight with Frida and Hjerterud, Selma feels lonely and wants to leave Snøfall, but Pil tries to convince her to stay; Winter is officially declared as the new Santa Claus.
Winter creates a bunch of new rules in Snøfall to get the calm and order he wants, and declares an official cleaning day; Selma decides to make up with Frida, but it proves harder than expected.
Selma, Pil and Frida seek to find out who Julius's "secret friend in the garden" might be; Håkon tries to get other children to leave letters in his Santa mailbox, a solution that could benefit both him and Ruth.
Selma, Pil and Frida sneak into the garden to look for Julius's secret friend; Winter is frustrated when people don't follow his new rules; in Ruth's bookshop, new customers are streaming in, and the letters in the Santa mailbox are gone.
Selma, Pil and Frida sneak out at night to look for the night birds that Trixter told them about; Håkon's father drops by the bookshop to see the new book and Santa letter business for himself.
Selma, Pil and Frida find out that Trixter has Julius's sled for safe keeping at his place; Ruth struggles to make sense of the things that happen at the bookshop.
Selma, Pil and Frida try to make sense of what the Oracle told Selma, and to find out where the Shadow Cave could be; Ruth misses Selma so much that she considers doing something she never thought she would.
After figuring out that Julius is being held captive, Selma, Pil and Frida go into the much feared Darkness to find him; Winter closes down Hjerterud's bakery for good.
Julius finally returns to Snøfall and Winter is busted, but now they are in a hurry to fulfill all the children's wishes in time for Christmas Eve so the path to VU opens; both Selma and Pil get a surprise.
Christmas Eve is here, and Julius and Pil fight against time so they can go to VU and spread Christmas joy to everyone; Selma has to decide whether she wants to stay in Snøfall or go back home.
