When a decapitated body washes up on the banks of the River Loire in the ancient city of Tours, the reluctant juge d’instruction Matthieu Lombard is brought in to lead the investigation. But when Lombard’s young niece appears, the inquiry changes course. Suddenly immersed in another world – one of eco-terrorism, bio-medical research, French aristocracy and the violent forgotten underbelly of society – Lombard begins to make unexpected connections.

Can the brutal murder of a lonely man really be justified by a noble cause? Or are good intentions hiding darker motives, more cynical and more deadly?