What happens
Clark Kent and Lois Lane travel to the mountain city of Dierville to investigate a run of disasters that has gripped the town with fear. After their car nearly plunges from a damaged bridge over the Jefferson River, they meet the City Commissioner, who describes power failures, floods, and tremors with no clear cause. A railroad barge loaded with gasoline then breaks free and drifts toward the falls, and Kent slips away to deal with it. Back at the office, a radio report names the Yellow Mask, and a threat is revealed: the city has until midnight tomorrow to raise one million dollars. The episode is part of The Adventures of Superman series, first broadcast on March 25, 1940.
Dierville, a mountain city on the Jefferson River
Characters: Clark Kent, Lois Lane, City Commissioner, Perry White, Superman, The Yellow Mask
Listen for: The Yellow Mask's ultimatum: one million dollars by midnight tomorrow, or the city will be destroyed.
Written from the episode itself; it never gives away the ending. Every recording is remastered for the stream: cleaned of rumble, hiss and mains hum (and the old TV whine where we found it), then levelled in two passes to steady broadcast loudness, so one show is never quieter than the next.