Synopsis by Hans J. Wollstein
The conclusion of chapter 10 left Bob Elliott (Edward Norris) gasping for air in a sealed room quickly filling with gas. In chapter 11, Pamela (Lois Collier), who is visiting with lady botanist (and secret Nazi spy) Dr. Elise Bork (Tala Birell), hears Bob's frantic knocking but is unable to help him because of Denker (Walter Bonn), Bork's assistant, who pulls a gun on her. The sound of the approaching constabulary, however, causes a quick-thinking Elise to shoot and kill her subordinate, saving Bob in the process. No one buys the woman's cover story, though, and Pamela does a bit of snooping herself. Unfortunately, after blundering right into Lang (Douglass Dumbrille) the girl joins Godac (Clinton Rosemond), Kypa (Clarence Muse and Jungle Jim (Budd Buster), all of whom have been taken hostages by the Nazi spies, who wants to replace Godac with their own man, Maati (Napoleon Simpson). Meanwhile, Bob and Chuck (Eddie Quillan) discover a secret Nazi telephone and follow the wire into the jungle. But unbeknownst to the Americans, a couple of Nazi henchmen (George Eldredge and Peter Helmers) are on to them and as they enter a cave the entire mountain seems to explode.