Published in Detective Comics #29, July, 1939, 6 pages.
After the U.S. Espionage Bureau (new name there) unscrambles a broadcast of what seems like just weird sounds, they discover a message talking about the need to get important papers from a Colonel Walsh at Fort Lannar. Bart Regan and his partner, Jack Steele, discover that Walsh is being set up for a fall by enemy agents.