Published in Detective Comics #14, April, 1938, 4 pages.
After receiving a cable urging them to return to the States at once, Bart Regan and Sally Norris head home where they are immediately handed an assignment on behalf of the Army Intelligence Staff. "Dr. Hornbeck is going to demonstrate his latest startling invention, nature unknown, this afternoon -- You are to guard him from harm." Unfortunately for the scientist, he is murdered before the pair arrive. Regan recognizes the assailant from the description so off they go to capture him and retrieve the new weapon he stole.