In Casablanca, a young boy named Walid is kidnapped in a mysterious van. At the same time, in Paris, the lieutenant of the BAC, Lucie Henebelle, begins to cry tears of blood and shoots her partner.

Sharko integrates Lucie into the crime squad. They investigate the medical files kept by Clinic Moreau and discover the images of the film entitled Syndrome E.

Lucie is more and more disturbed by this syndrome, which seems to be able to tip her at any time into ultra-violent crises. Sharko sees her distress, and their mutual attraction grows.

Sharko leaves to investigate in Morocco. He is received by the officers of the Casablanca criminal brigade, who end up setting a trap for him; Lucie continues her investigation of the Moreau Foundation.

Sharko tries to track down Walid, who has travelled to France for a mysterious final experiment; Lucie makes contact on the internet with a mysterious interlocutor in Canada and takes off for Montreal.

At the Montreal archives, Lucie finally tracks down the little girls from the old film; Sharko gets kidnapped and ends up at the very heart of the final experience.