Courier Tom Jessup loses track of a briefcase containing something vital: spores. These organisms, properly nourished, will grow into aliens able to tolerate Earth's high oxygen content. Through mischance, Jessup loses track of the briefcase, which changes hands several times. Finally, some kids wind up with it, and meanwhile inside it the spores continue to grow, and outside it, Jessup is increasingly desperate. Written by
Did You Know?
The invaders are seen for perhaps the first and last time as spores growing into "infants" that appear to be slimy, brown-and-green-tinged blobs. They have neck-less heads and each is seen to be forming a pair of stubby arms. Of course, this is only what their young look like. See more
During the fight in the diner, the stunt doubles for Roy Thinnes and Gene Hackman are obviously not Thinnes and Hackman. This is especially obvious in the case of Hackman who is balding while his double has a full head of hair. See more
The destruction of the alien spores becomes a major victory for David Vincent - a continuing, relentless war in which victories are few.