What happens
Superman's secret identity, Clark Kent, is pursued by Sidney, a cunning international spy in league with the Nazi Henry Miller. Sidney invites Kent to his country house, claiming to have uncovered Superman's double identity. Sidney says he has studied Superman for years and presses Kent to admit the truth, warning that a more powerful enemy is hunting Superman. Kent, wearing a detector belt, senses atomic energy and grows weak as Sidney opens a lead-lined closet. The episode ends with Kent collapsing as the Atom Man advances, and the outcome left unresolved until the next installment.
Sidney's country house and study in Metropolis
Characters: Clark Kent, Sidney, Henry Miller, Superman
Listen for: Sidney's accusations that Kent is Superman, and the detector belt sounding a warning as Kryptonite is detected.
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.