Arne was employed by the Danish Defence Intelligence Service during the Cold War. He tells of how the service obtained information from the extremely closed Soviet Union. Mona was recruited by the service at the age of 30 and went to Poland with an experienced spy.

In 1959, Niels was employed in the most secret part of the service. Not even his family knew where he worked or what he did. Matilde Kimer goes to Spain to meet Jens, who was arrested in Poland in 1987 and convicted of espionage. But behind the scandalous case lies a spy story that was actually a success.

As a seasoned spy, Mona decides to take her husband and children on a trip to Poland under the guise of a family vacation. Many years later, she is excited about their reaction to her involving them in the risky mission. In 1987, Jens set off on trip no. 13. It was his last trip for the service.