A group of students investigates a series of mysterious bear killings, but learns that there are much more dangerous things going on. They start to follow a mysterious hunter, learning that he is actually a troll hunter.

Former childhood friends Christian and Erland, now in their late 20s, are confronted with their own adolescence as they go searching for Christian's estranged little brother in a scene they're not familiar with - contemporary youth culture.

The film is based on a 2003 novel by the same name, written by Norwegian author Jostein Gaarder. The main character is the young boy Georg who one day finds a long letter from his deceased father. The letter tells, among other things, about the father's youthful love for the mysterious "orange girl" (appelsinpiken), and leaves a mystery for Georg to solve.