The Doctor and Peri's partnership tested by the Doctor's instability and Peri's growing reservations about his methods

The Doctor attempts to soothe Peri’s exhaustion and dread with a recital of Longfellow’s poetry as they approach the alien dome. His effort at levity contrasts sharply with the mission’s …

Lang’s panic in the TARDIS underscores a universe teetering on collapse as the Doctor studies the Jacondan twins’ equations. Peri’s earlier discovery of the countdown has sharpened the threat to …