Our vigilante and his friends are trained on the Island of the Conque on which the Ecarlate Rose will join in friendship with a master of out-of-pair weapons and discover many mysteries. Maud and Guilhem meet Num, a fishman who watches over Marina from the sea. Loïc, jealous of this man who seems to have bonded with friendship with the woman whom he covets, kidnaps him in order to use his powers for unworthy purposes. Our vigilantes will help Marina to save him and break the secrets hidden by the sea together.