AllMovie

Everybody, including Officer "444" (Ben Wilson) and Nurse Gloria Grey (Neva Gerber), evacuates the police van seconds before it crashes into a ravine. The Frog and his gang find momentary shelter at an abandoned mine but "444" and the "Flying Squad" raid the hideout. Gloria and Frank Haverly (Phil Ford) are saved but The Frog himself manages to scurry away. Police Chief August Vollmer makes the capture of The Frog top priority and the "Flying Squad" is ordered to use the latest crime detecting techniques to track him down, including a new invention, the "lying machine." The trail leads back to the sewers below the Dragon Café where The Frog, now unmasked as Dr. Blakley (Al Ferguson), manages to trap the entire police force before the place suddenly explodes.