A friend of Leo Saint-Clair, Jacques d'Hermont, calls for his help because he and his family are slowly dying from of a mysterious disease. The Nyctalope investigates and discovers a new, deadly foe: Armand Logreux d'Albury, the so-called "Master of the Seven Lights," lurking in the Castle of The Cross of Blood... Six years later, the Nyctalope crosses paths again with Logreux d'Albury and another of his arch-enemies, Engineer Korridès, while his son, Pierre, is on a perilous expedition in Africa searching for the legendary Tower of Babel... Leo Saint-Clair, alias the Nyctalope, was created in 1911 by Jean de La Hire, one of France's most prolific serial writers. Gifted with night vision, hypnotic powers and an artificial heart, Saint-Clair is a fearless hero who battles colorful super-villains. This book includes an original novel by La Hire penned in 1941, and a new sequel written by Emmanuel Gorlier.