In the aftermath of the 13 November 2015 attacks in Paris, an extraordinary investigation was set up involving more than a dozen European countries and the United States. This diplomatic, judicial and intelligence cooperation changed the face of Western counter-terrorism. Through the testimonies of judges, politicians and intelligence officials, 13 November 2015: Anatomy of an Investigation recounts the unprecedented international judicial investigation that lasted 5 years. From the setting up of the investigation to the discovery of the extent of the networks, from the first diplomatic knots to the neutralisation of the masterminds, the film takes a close look at the flaws and successes of the V13 investigation and the fight against Daesh.