In this documentary series, Petter Nyquist lives like a regular prisoner in Halden Prison for 30 days. Side by side with murderers, robbers and notorious criminals, he gets a unique and personal insight into everyday life behind bars in what's referred to as the world's most humane prison. After he gets out, he continues to follow the inmates for a year, trying to understand how they are shaped by their sentence. Does the punishment work? Are they rehabilitated?