1862. French intervention in Mexico. Napoleon III's expeditionary force is trapped. The young commander of the volunteer detachment, who was given the nickname Captain Mercury for his indomitable vitality, was entrusted with reconnaissance of the situation. Without hesitation, he is ready to give his life for his native France. But he has no right to be killed, because a strong, unkind feeling has long lived in his soul... The next volume of Louis Bussenard includes the novel "Captain Mercury" adjacent to the Zouave cycle and an old translation of the novel "The Orphan of Montmartre" lost on the pages of French newspapers.