What happens
On the Magic Isle of Euchlydia, Jerry and Joan wait with the help of the Euchlydian submarine commander, who has joined the Gregory Party, for the right moment to enter the main chemical laboratory. There, the scientists are watching G-47 complete a formula he believes to be Captain Bradford's Universal Solvent. Jerry and Joan explore the secret sound channel, where some floor strips and tools are treated to be silent and others are made deliberately loud. The commander returns and says the experiment is nearing completion, and she brings the two into the laboratory as her prisoners. G-47 keeps them close by, and the formula reaches its boiling point as the scene ends.
The secret chambers and main chemical laboratory of the Magic Isle of Euchlydia, including the sound channel on the lower level
Characters: Jerry, Joan, Commander, G-47, Captain Bradford
Listen for: The sound channel, where noiseless paint, tools and soundproof corners contrast with loud ones, and the moment G-47 says the formula has reached its boiling point
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.