During a vacation from the planet Blob, four aliens experience a spaceship breakdown. Accidentally leaving relatively intelligent Bernard (Mel Smith) in space, the remaining crew -- Julian (Paul Brown), Desmond (Jimmy Nail) and Sandra (Joanne Pearce) -- crash into Earth, landing in the United Kingdom. Despite their stupidity, the extraterrestrials become celebrities. Meanwhile, Bernard tries to pursue them after arriving in Arizona, but his claims to be an alien lead to institutionalization.