When private eye John Hillman is on assignment in London his wife Kajsa visits the Army's riding school at Strömsholm, Sweden. She gets involved in the strange murder of the Blue Rider. Unknown to everyone at Strömsholm.
Teacher Rundqvist who works in a school in a small town in Scania is old fashioned but loved by his pupils. When a younger teacher with new ideas of teaching starts at the school Rundqvist's methods are questioned.
