Valley of Eagles

Dr Nils Ahlen's invention allows huge amounts of energy to be stored, as audio recordings, on barium discs. When played back, the discs release enough power to fuel a small town or "propel a rocket or flying bomb across the Atlantic" Ahlen becomes impatient with the attitude of police inspector Peterson and, having established that his assistant Nystom is also missing, begins an investigation of his own. The chase takes all four protagonists into the territory of the local Sami people, referred to here as Lapps.