A group of scientists investigate a deadly new alien virus before it can spread.
Science fiction in the full sense of the word: an instant classic! Its aesthetics, especially the split-screen, may seem a bit dated, but they do fit the topic well.
On renewed viewing: again, it's pure science fiction.
Halliwell**: "Solemn and over-detailed but generally suspenseful thriller, with a sense of allegory about man's inhumanity to man."
Maltin**1/2: "Overlong sci-fi thriller..."
Psychotronic/Michael Weldon: "An excellent big-budget technological thriller...With great special effects by Douglas Trumbull and an exciting climax with James Olson vs. a computerized laser beam. A pretty terrifying look at the future (present?)."