What happens
Superman and Professor Timothy Twiddle search for Jimmy Olsen, who vanished into an underground river beneath the surface of the moon. Jimmy's voice can be heard, but the meteoric soil blocks the man of steel's X-ray vision. Superman and Twiddle encounter hundreds of yellow-eyed, scaly, toothless lizard-like creatures that gather near the water. Jimmy describes how the creatures carried him into a cave, then retreated back into the river. Superman tries to blast a route through the cave walls, but he falls through a wall, and the cave seals behind him. Jimmy and Twiddle are left stranded in the dark cave, while Poco is still missing.
The underground caverns and a river beneath the surface of the moon
Characters: Superman, Jimmy Olsen, Professor Timothy Twiddle, Poco
Listen for: Jimmy's voice calling out from the river and cave, and the lizard-like creatures' noises
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.