I've seen just about every episode of the Twilight Zone, and I can say with relative confidence that this one scared me the most (and still does). Yes, it's pretty obvious what's really going on by the time it's revealed but people who say this is a detriment to the story misunderstand that this is really a suspense story not a mystery. The main source of anxiety on the viewer's part is the question of "when will Helen figure it out? Will it be in time?" The moment of realization for Helen is paired with the scariest cut in Twilight Zone history (in my opinion). The acting is really great and the casting was perfect.