The third volume in a series of Karlsson on the roof, which ” is extremely wise and as a stout man in the best years,” he says. It is also the best expert on everything. Equipped with distinctive, propeller, can fly over Stockholm and play pranks … Karlsson gets into a real trouble. He is suspected of espionage. His parents are away and the usually quiet house sees ghosts appearing, the witches fly on broomsticks outside the windows, and at night burglars roam.