Book is in French In this tenth novel, the Three Musketeers find themselves immersed for the first time in an adventure that takes place at home, in the Greater Moncton region. When a journalist announces that the footprints observed in the mud of the Petitcodiac river are those of a formidable creature hiding in this "chocolate river", the young detectives decide to carry out their own investigation. And while unusual observations multiply, world-renowned scientists, friends of Professor Jarnigoine, disappear one after the other, leaving behind traces of mud. In a world where fake news is increasingly difficult to distinguish from reality, Gabriel, Ania and Mamadou will have to shed light on this story if they want to avert the danger that the Petitcodiac creature poses over the city - and solve the disappearance of scholars.