A horribly mutilated corpse, suspended between heaven and earth in the mountains of the Grenoble region. A grave — that of a little boy — mysteriously ""visited"" during the night, while the files concerning him vanish from his school. Two enigmas that two extraordinary cops set out to solve: Pierre Niémans, a brilliant officer whose unorthodox methods have jeopardized his career, and Karim Abdouf, a former delinquent turned cop, whose skin color and dreadlocks provoke distrust in the provincial backwater where he's been assigned...

The two cases will come together, and the two men will recognize each other. Together, they will trace the terrifying secret of the Crimson Rivers.
A secret that will only be revealed in the final pages of this exceptional thriller, written by the author of The Flight of the Storks and adapted to the screen by Mathieu Kassovitz.