This is one of the best of the original Outer Limits, but I've noticed over the years that it's sadly underrated. The premise is classic science fiction and the acting is superb. If this were a b-horror movie of the time, I'm sure it'd be well regarded today. You have to overlook the special effects, of course, but this is true of anything contemporary be it "The Day the Earth Stood Still" or "The Day of the Triffids." The powerful, poetic drama of the ending is both life-affirming and morally uplifting. But then, that's the "Outer Limits" at it's best.