The brand new prison of the municipality of Haren is ready for use. Six professionals who decide on detention on a daily basis, including a prison director, a judge and the Minister of Justice Vincent Van Quickenborne himself, allow themselves to be locked up for four days to test the effect. They share their cell with ex-convicts who have already served their sentence. As the brand new cellmates settle into their new environment, they think aloud about the usefulness of prisons and their role in it.