 The seventh of Universal s sound-era serials (slid between two Tim McCoy serials, "The Indians Are Coming" and "Heroes of the Flames") has secret service agent Gary Gordon (Kenneth Harlan) assigned to run down a band of smugglers known as the River Gang. Unknown to him, John Mackey (William Worthington), father of his sweetheart Lola (Edna Murphy), is a member of the gang. When Mackey s partner Joe Burke (William Thorne) is killed, Kent Martin (Gayne Whitman) claims he has evidence that will convict Mackey of the crime, and tries to blackmail Mackey to gain his consent to a marriage with Lola. The latter is not thrilled at this prospect and even less thrilled is Martin s sweetheart Jane Madden (Gertrude Astor). When the blackmail ploy fails, the ever-romantic Martin kidnaps Lola and takes her to his cave hide-out.