What happens
Clark Kent and young Jimmy Olsen confront a man hiding a speedboat on a cove near a spy gang's former hideout, and recognise him as Lewis, the Secret Service man they had thought was dead. Lewis explains he was shot at the gang's shack in the woods and survived. Kent and Lewis discuss Dr. Deutsch's operation on Volcano Island, where radium is being mined for his master plan, and the boat that blew up. The group plans a return to the island by seaplane, and Kent insists Jimmy stay behind before a reluctant Mr. White is brought along. On the island, Lewis suddenly turns on his companions and takes them prisoner at gunpoint. This is the Adventures of Superman series, with the story from the Part 11 episode, which aired June 18, 1941. The lead actors are not named in the transcript.
A cove near the espionage gang's former hideout, a seaplane flight to Volcano Island, and the island itself.
Characters: Clark Kent, Jimmy Olsen, Lewis, Mr. White, Dr. Deutsch
Listen for: Lewis turning on Kent, Jimmy and Mr. White at gunpoint on the island.
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.