Their son is a criminal and they will bear this cross forever. They are the parents of Matthieu, who in 2011, at a boarding school in Chambon sur Lignon, killed his friend, Agnès, who was 13 years old. To date in France, Matthieu is the only person to have been sentenced to life imprisonment for a crime committed when he was a minor. But for his parents, consumed by guilt and shame, life must go on… They keep standing, because their 17 and 11 year old daughters need them, and because Matthew remains their son, for life.

This film takes a transversal look at parenthood. What do we pass on to our children? How can we help them when we feel that they are out of their depth? And when we are brutally confronted with their insanity? Can we, as parents, overcome the failings of institutions? Can we continue to support and love a child murderer? And how do we carry on living with the children who remain, or maintain a relationship during such a terrible ordeal?

This is the story of a woman and a man who aged a thousand years in a matter of months, who look back over the past and dread the future. The story of an ordinary and heartbreaking couple, of parents who continue to worry about their child, who is, at last, being treated for severe mental health issues.

Once a week Sophie and Dominique go to see their son in prison: a six-hour drive for a forty-minute visit. They never know what state they're going to find him in. On many occasions, Matthew has asked them to forget him, to leave him, and to rebuild their lives without him. But they know they will never give up, and that, despite being a killer, he will remain their son. For life.