Young European and American students are trying to find evidence for the innocence of prisoners, whose cases even top American lawyers don't dare to tackle.

Chicago. A man has been innocently imprisoned - for more than twenty years. All claims have been rejected. He is condemned to life sentence. His only chance: a handful of law students. At the Northwestern University of Chicago, several groups of students are working on cases that even top American lawyers don't dare to tackle: cases of innocence without DNA proof. Legal exercises with real peoples' lives: there is no evidence of the guilt of the people they look after - but no evidence of their innocence either - only the prisoners' own statement. Among others, European students take the chance to be part of each group of prospective lawyers during their university exchange program, and be part at the exciting search for clues in the gangland of Chicago.

In search of proof of the innocence of the prisoners the undergraduates encounter shady witnesses, corrupt and violent police officers and not very credible experts. The search is frustrating and dangerous. And still, the young people manage again and again to free the detainees that they have taken on.

The series tells the story of prisoners and their sideline European and US heroes - students at the Northwestern University in Chicago - in documentary form, partly recorded by the students themselves. The individual episodes follow several plots investigated by different groups at the same time: the beginning of one case of innocence, the investigations of another and a new trial with an exciting or knockdown ending.