Maurice Leblanc, the author of Arsène Lupin, is in Brussels for a report and meets the handsome Jean d'Aspry, Arsène Lupin's temporary identity. One evening, Leblanc receives a mysterious message: “Whatever happens, don't move, or you're a dead man”. Terrified, Leblanc spends a very bad night in a house full of extravagant commotion. The next day, he is shocked to read about his night in the newspaper.