What happens
Jerry and Joan, visitors to the Magic Island of Euchitia, look out from a balcony over a vast undersea cavern where a community is at work. Trees and plants grow there despite the absence of sunlight, and Jerry and Joan are eager to explore. They discover a stairway that ends short of the floor, then a hanging platform that carries them downward. Along the way they meet the submarine commander, who guides them through a steel walkway and corridor and warns them about questions and conduct. The Magic Island series is the setting, and the commander holds them to Euchitian rules.
The colony of Euchitia on the Magic Island, a large cavern 300 feet below the ocean surface
Characters: Jerry, Joan, the submarine commander, G-47, Thales
Listen for: The hanging platform descending silently, the steel drawbridge lowering from the cavern wall, and the commander's warnings to Jerry about his questions
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.