Mister No’s life is hard in the penitentiary on the island of Approuague, where he is forced to contend with the guards and the other lifers (in particular the violent Dega). However, when Jerry saves the life of Monique Valont, the daughter of the Prison director, things improve. In the meantime, at Cayenne, Esse-Esse sets off on the search for the mysterious Alan Marcel, convinced that he can clear Mister No’s name….