In old detective novel style, this documentary tells the fascinating story of the research conducted on the remains of Agnès Sorel by the anatomical pathology team of Doctor Charlier at the CHRU hospital in Lille, France. By exhuming the bones contained in the grave of King Charles VII's favourite and by analysing her teeth, scientists succeeded in determining that it was a blonde woman aged 25-26 with three children. The film also retraces the profile of the first official mistress of a king of France, who influenced the Monarch's decisions and had a bearing on the future of the Kingdom. Agnès Sorel created a scandal in this latter Middle-Ages era with her liberal attire, political influence and relaxed attitude and behaviour. The team of Doctor Charlier not only identified the remains of the favourite, but also discovered the cause of her death: poisoning with mercury. Who could have been interested in the death of Agnès Sorel?