What happens
Clark Kent and Lois Lane are in the town of Direville, where the mysterious Yellow Mask has threatened to destroy the city unless it pays a million dollars. After strange explosions shake the Harley Dam, Kent receives a letter warning the city commission that the Mask is growing impatient. Kent suspects the Mask may be planning something other than blowing up the dam. Kent slips away to investigate underwater, where he finds a piece of polished metal lodged against the dam, and then changes into Superman to act on what he learns. The story is part of the Superman radio transcription series.
The town of Direville and the nearby Harley Dam and Harley Lake
Characters: Clark Kent, Superman, Lois Lane, Yellow Mask, City Commissioner
Listen for: The explosion felt under the water near the dam, and Kent's sudden suspicion that the Yellow Mask has another scheme in mind
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.