What happens
Captain Tex Bradford, Jerry Hall and Joan Gregory are hiding in a stolen Euclidean submarine one and a half miles beneath the South Pacific, anchored and 500 miles from the Magic Island. Pat Gregory, unsure whether the Euclidean scientists can be trusted, argues with Jerry about their intentions. A message arrives from Johnson, who is in Los Angeles and warns them to hold back. Tex has hidden his formula in a bank vault protected by a compound that would destroy it if the vault is opened improperly. Johnson's radio signal fails, and an unknown voice demands that they surrender the formula within ten seconds.
A stolen Euclidean submarine anchored 9,000 feet below the South Pacific, 500 miles from the Magic Island, with radio contact to Los Angeles.
Characters: Captain Tex Bradford, Jerry Hall, Joan Gregory, Pat Gregory, Johnson, Albert G-47
Listen for: The ten-second ultimatum from the unseen Euclidean speaker and the group's decision on whether to answer it.
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.