Slimy, disgusting aliens invade Earth. They attach themselves to peoples backs and control their minds. Sam Nivens (Eric Thal), father Andrew Nivens (Donald Sutherland) and Mary Sefton (Julie Warner) are all part of separate government agencies who join together to fight the invasion.<br /><br />Not a faithful adaptation of Heinlein's book but still a good film in its own right. The script is good; it has realistic, believable characters; the aliens are agreeably disgusting and the action scenes are good and violent. Also, with the sole exception of Sutherland (who appears to be sleepwalking) all the acting is good--especially Thal (tall, handsome and hunky) and Warner (beautiful, intelligent and strong). A very good sci-fi film. Also, I agree with some previous posters--one of the best scenes in the film is Thal's nude shower scene. Woof!