A low-budget kiddie sci-fi flick from the same period that brought us "Earth Vs. The Flying Saucers," and interestingly enough starring the same actor, Hugh Marlowe, a sort of older version of that other '50s sci-fi star, Richard Carlson. Four astros headed for Mars go through a time warp in space and end up on Earth after atomic Armaggedon has decimated the planet. This makes things convenient both set- and costume-wise, as all the cities and highways are gone and all that's left on the planet's surface is a bunch of murderous cavemen. Ah, but inside one particular cave, the astros encounter an underground habitat containing what's left of humanity. The plot is sort of H.G. Wells' "The Time Machine" in reverse. Because the story is actually interesting (the sun-deprived humans are dying out and the astros try to convince them to return to the planet's now-decontaminated surface), it's easy to forgive the theatrical photography, cardboard sets, and the three '50s-type females in their restaurant hostess outfits and bouffant hairdos. One way or the other, the always-dependable Marlowe keeps everything nicely grounded as the leader of the astros. The film looks like it cost $1.98 to make, but a reasonably strong story and decent-enough cast make it worth a glimpse. A young Rod Taylor. the Russell Crowe of his day, plays one of the other astros -- although he's given little to do except to bare his chest and make the ladies swoon.