Noel White, a trainee at the Santa Company, prepares for her exam to become an official Tonttu. Her assignment is "To find the most important thing for a Santa Claus." As the deadline approaches without an answer, a single letter from a child arrives late at the company. Just as the letter is about to be processed as a defect, Noel and her friends embark on an adventure to deliver the present—but will Noel discover the answer to her assignment? Set one year after the events of the novel.