A former police officer, Marc Lorca, sees his wife die from a terrible car accident, which occurred while he was driving. Previously alcoholic, Lorca seems to collapse under the weight of guilt. But a former colleague, Marianne Duriez, recently become a police captain, shows him that the accident is not accounted by any negligence on his part. The survey of experts has indeed revealed that the steering axis of the vehicle was sabotaged. Gradually, the suspect list is expanding. Lorca realizes he knows nothing of the past of his deceased wife, who was obviously part of a small extreme left group.

Ce soir-là, Agnès a une grande nouvelle à annoncer à Marc, son mari. Mais elle meurt accidentellement, la direction de sa voiture ayant été trafiquée. Dès lors, Marc, ancien flic, ex-alcoolique, ne va cesser d'apprendre des nouvelles troublantes sur le passé de celle qu'il a aimée. Agnès était enceinte. Femme lisse et sans histoire en apparence, elle avait fait partie des Factions rouges, groupe d'extrême gauche favorable à la lutte armée. Complètement sonné, Marc rencontre ses anciens collègues chargés de l'enquête. Parmi eux, Marianne (excellente Isabelle Gélinas) dirige les recherches.