Ineffectual dreamer Des Kinvig (Tony Haygarth) runs a rundown little electrical repair shop in the small town of Bingleton where he lives with his mumsy, scatterbrained wife Netta (Patsy Rowlands) and oversized pet dog Cuddly.

However, after encountering a flying saucer while walking the dog one night, Kinvig discovers she is actually a scantily-clad alien from the planet Mercury who desperately needs the help of the scruffy, bearded Des' "exceptional brain" to stop an invasion of the evil ant-like Xux who are replacing people with robot duplicates.

Kinvig's friend Jim Piper (Colin Jeavons) is a lifelong UFO watcher and wild-eyed conspiracy buff who is consumed by jealousy when Des tells him about his extraterrestrial exploits.

In early 2004 it was reported that Edgar Wright was working on a script for a big-screen adaptation of Kinvig; however although initially green lit, the project was eventually dropped.

Nicholls also noted that some viewers objected to Kneale's depiction of science-fiction fans as being the same as UFO enthusiasts, and states Kinvig is notable for its "contemptuous treatment" of the leading characters.