When Thomas´ sister dies in an accident, he discovers that her death may be connected to their deceased father´s work in military intelligence. As Thomas embarks on an investigation he soon finds himself and his family under surveillance by an unknown group of people.
Three 13-year-olds start a detective agency and in solving their first case, learn about friendship and courage.
The film is based on Christian Kampmann's novels: "Certain Considerations", "Solid Relationships", "Clean Lines" and "Other Ways" (1973-75). The Gregersen family is a picture of inner and outer Denmark from the mid 50's to the 70's. The story begins in 1954 in the well-behaved, but not just successful, Gregersen family from the best part of the whiskey belt on the right side of Strandvejen.
