Dr. Miller, Uncle Louis, Mrs. Werner and writer Harry - four classic characters. Who is evil and who is good - it is not entirely clear. But it requires the youngsters Kaj, Peter, Marianne and six year old Tommy to figure it out during an eventful summer on idyllic Kullen in Skåne. Espionage, mysterious lights and strange code words suddenly become a part of everyday life, but also wild hunts in min shafts, kidnapping and nighttime burglary. It will be a summer they will never forget.