The Oslo police received information about the illegal acquisition of a rare and very scary weapon - a Merklin rifle with an optical sight, prohibited for sale by the German authorities. It is possible that the copy was purchased by a collector, but detective Harry Hole's sixth sense tells him that a buyer must be found as soon as possible. The search leads to the events of World War II, when Norway had to choose between two threats of the 20th century: the red and brown plague. However, the investigation reaches a dead end, and more and more corpses appear in the case...