Headline: Marcos, a middle-class teenager, kills his father and leaves one of his four siblings badly wounded.
The first reactions: Friends, family, Marcos's teachers: no one can understand what happened. No one foresaw it. The media is full of images of the murder. Once again, teenage violence monopolises the news.
The investigation: Marcos's crime is not an isolated event. There have been all too many cases of minors involved in violent situations in recent years. Physical and cyber-bullying. Racist attacks. Drup peddling. Videos on YouTube humiliating teachers. Depressed school staff. Academic failure… Is it the teenagers' fault? Or their teachers? Their parents? Is anyone really guilty or are we all victims?
A journalist, urged on by these questions, decides to look into the murder. What happened on the day of the crime? The week before it?