A 12 episode serial starring Rex, the King of the Wild Horses and Rin-Tin-Tin, Jr. Rex is brought from the island of Sujan, where he is worshiped as a God-Horse, to the U.S. to be trained as a polo pony. He escapes, meets Rinty and with the help of Frank Bradley is returned to Sujan. The natives have been persuaded to turn against their God-Horse, however he is rescued just in time before he is burned as a sacrifice.

After Tarzan's estate is destroyed by Arabs Jane is sold into slavery by a man posing as a friendly scientist. Tarzan develops amnesia after a blow to the head. When he recovers his memory (from a later blow) he defeats the villain, recovers the fabulous jewels of Opar, and rescues Jane.

A newspaper publisher and his Korean servant fight crime as vigilantes who pose as a notorious masked gangster and his aide.

Cowboys and a businessman compete to find lost treasure.  

A mad scientist tries to sell his formula for a dist integrating gas to foreign powers.

A murderous gang of counterfeiters has kidnapped the government's best engraver and is forcing him to print virtually undetectable phony money. The Secret Service sends its toughest agent, Jack Holt, and a female partner after the gang.

A madman sets out to destroy a group of Chinatown merchants.