Two years have passed since the event of Mermaid Project, and Romane and Brahim have paid the price of their courage and integrity. Ignored, even censored, by their superiors, they're now reduced to taking lousy private eye jobs to earn a living. Meanwhile, though, the same cetaceans whose advanced intelligence the UN had refused to believe in are attacking fishing trawlers ... with rockets! Before long, the authorities ask our two investigators to take their old jobs back ...