You get a bit of "The Thing" and maybe some "Ice Station Zebra" with this little fast-paced, gripping entry in the series. Sci-fi plankton that can split bulkheads, foreign powers, and undercover enemy agent sabotage all configure for a suspenseful episode packed with incident. The plankton monsters really don't come off as silly as they should be and are actually kind of menacing. A nice camera pan is used at the beginning, and you get some effective odd-angle, shadowy corridor shots and close-ups; the cinematography in these early b&w episodes added a lot to the stories, for me at least. Guest stars: David Opatoshu, a prominent figure in Yiddish cultural endeavors, plays an ex-Nazi scientist; Jill Ireland I would imagine is the most recognizable name here, playing an agri-chemist with big hair. At the time this was made she was married to David McCallum of "Man From Uncle" and more currently "NCIS" fame; she would go on to be more well-known as Charles Bronson's wife and co-star in several of his fims. My favorite among the guest players, though, was David Milford, as the representive of the commercial backer for the venture. He was really good, lots of personality in his performance, and gave the proceedings a little bit of an " 'Alien' on the Seaview" feel, with him in the Paul Reiser role. Gripe: the kissy-cute dialogue of the husband-wife ice-station scientist team at the beginning, and why couldn't they hear the monstrous plankton growing when I could?

I like the deadpan look on the Admiral's face when he says "You can't go through there. It's alive with plankton."I also notice he didn't mention it was giant people-eating plankton!

Sort of like the Creeping Terror, that was a sort of plant thingy from outer space. The Nazi'sw get drag into this too but, at least back then people seem to have had a healthy opinion about Germans. Are these plants or plant-animals of some sort? what was it with people back then and plants?