Quick recap
An American tycoon arrives in Paris, followed by a criminal gang after his fortune. Caught in the middle are the tycoon's daughter and Arsène Lupin, who gets close to both under a false name and tries to stop the scheme. It's the last Lupin novel Leblanc published, first as a newspaper serial in 1939 and then as a book in 1941, after the author's death. The 1941 edition dropped a chapter, leaving holes in the plot for decades; the full text wasn't recovered until 2002.
