This article about WW1 secret warfare investigates the life and death of the biggest French network in occupied territories and its leader, Oscar Hernalsteens. This case study examines how a major figure of the secret war failed to become a heroic figure of the national memory in Belgium and France. It first evokes the tragic circumstances of Hernalsteens,condemned to death by a German military court and allowed to get married on the eve of his execution, on 19 April 1916. Our investigation returns then on the troubled past of Hernalsteens, tried twice before the war, first for a successful theft, then for a failed assassination attempt, and described as an “anarchistâ€. Working in France after his liberation, Hernalsteens was recruited by the French Deuxième Bureau and sent back in his occupied homeland to gather military information on the enemy. Crossing the borders between France, Belgium and the Netherlands many times, Hernalsteens built a dynamic and extended network staffed with at least 141 agents, centered on Lille, but covering several French departments and Belgian provinces. With the help of social networks analysis, the article considers then weaknesses of the network, namely its lack of compartimentation, and how the German secret polices suddenly dismantled it at the end of the summer 1915. Finally, it contemplates how, despite his intense activity and his tragic fate, Hernalsteens failed to become a major figure of the secret war in the collective memory. Crossing too much frontiers, not only national, but also moral,did help him to develop his secret ventures, but not to attract enough consensus to emerge as a national hero.