Early Universal serial concerns the quest for the two halves of a sacred disc on which is written a formula of great value. Beginning in China during a revolution the the adventure shifts to various locations around the world. To be honest the first four episodes of the this serial are four of the best in serial history. There is a sense of urgency and speed with which things move that keep things moving lively. The first chapters set in the city under siege are amazing, its large scale danger through which the heroes and villains move and its amazing. Unfortunately the need to find the disc and then get out of the city is lost once the story moves on to the jungle where the round and round about nature of the story becomes not much more than spinning wheels. It remains watchable thanks to the great cast, especially John Davidson as the villain. Also helping to keep it watchable is some great location footage thats added in for color. Worth a look.

Pauline uses many forms of transportation on her quest for the secret formula for the invisible gas that destroys civilizations. Among them are several airplanes. In episodes 5 and 6 there are good examples of single engine airplanes from the early 1930's. Later, in episodes 7 and 8, Pauline is shown as a commercial passenger on a huge multiengine flying boat. The serial includes historic shots of the take off and landing of the 12 engine Dornier Do X flying boat, the largest and most powerful airplane ever built when it was completed in 1929. It was so heavy that the 12 600 horsepower engines could only lift it to 1600 feet! It was so clumsy that the passengers were asked to crowd together on one side when the airplane was turning. It held the record for the most passengers (169) in one plane. That record was not broken until 1945.The Do X made only one transatlantic flight, via Africa and South America with 100 passengers. It landing in New York City on June 4, 1931. When it finally returned to Berlin, it was retired and placed in a museum. Episode 8 shows the festivities associated with that historic landing. There are shots of actors boarding the plane, and some interior shots as well. The images of the Do X are the high point of the entire serial.

An enjoyable cliffhanger from Universal's early sound serial period with a good cast and storyline. Somewhat dated production hurts it a bit but overall an admirable effort from producer Henry MacRae and director Ray Taylor.

Evalyn Knapp gives a pouty performance as she, along with her father and various accomplices, attempts to locate the other half of a disk which contains an important formula, before the evil Dr. Bashan gets his hands on it. Lots of humor and cliff-hanging action. If you liked this serial, try "The Black Coin".