Robin [Dick Grayson]; Mystery Analysts of Gotham City [Art Saddows; Batman [Bruce Wayne]; Commissioner James Gordon; Martin Tellman; District Attorney Danton; Kaye Daye; Professor Ralph Vern [as Mr. X] (villain)]; Mr. Mergen (jeweler)
Synopsis
The Mystery Analysts split up to search for the thief who purloined a valuable diamond, and it's Batman who discovers that one member of the Analysts is the guilty party!