Un amigo de William Legrand (un misántropo apasionado por la entomología ) y de Júpiter, su viejo criado, narra su participación en una aventura para resolver un complicado misterio. Éste consiste en descifrar un pergamino escrito en clave, hallado casualmente en una playa, que contiene las instrucciones para desenterrar el tesoro de un antiguo pirata.
A friend of William Legrand (a misanthrope with a passion for entomology) and Jupiter, his old servant, recounts their participation in an adventure to solve a complicated mystery. This consists of deciphering a scroll written in code, found by chance on a beach, which contains the instructions to unearth the treasure of an ancient pirate