Twilight - The time of the day when the sun is just below the horizon; the period between sunset and dusk, and between dawn and sunrise; A state of ambiguity or obscurity.

"It may be said with a degree of assurance that not everything that meets the eye is as it appears to be." 

~Rod Serling  

Episode 8: 

From the Original "Twilight Zone" 

A Quality of Mercy

by Rod Serling