It's Christmas Eve morning and the seven-year-old Sonja wakes up eager to check her advent calendar. There she finds a note from her uncle Henrik. The first riddle in a scavenger hunt which takes little Sonja through the house, into the garage, and into the forest to look for the nothern lights. In the snow, there's a surprise, but not what uncle Henrik placed there for her to find.

Originally released in 2018 as a Julehefte (a comic booklet released around Christmas), but was later reprinted in hardback format in 2020.