Donald Quick is recovering from a mental breakdown, following a freak hyperspace-fuel ingestion accident at the launch of an expedition to Alpha Centauri. The three spaceships have now vanished, but Donald, who remained on Earth due to an inner ear disorder, has become haunted by recurrent dreams of giant and hungry crustacean aliens. These are particularly nightmarish nightmares, such as the opening sequence where Donald finds himself in a finger-food bowl at an alien party waiting to be picked up, dipped in sauce and eaten alive.
The plot "twists" about half-way through, although this is not unexpected - psychiatrist Kelter's unconscious explanation of Donald's dreams is too elaborate and overconfident, and like Donald we never quite believe it. However it does introduce ideas of superiority and inferiority, and these themes are explored as the story brings together civilizations that differ in scale, intelligence and outlook.
Thanks to my sci-fi gene deficiency I was not deterred by the presence of characters such as Priestess Poogli (the Gordon Ramsey of the macroverse) or Kalnischeoraphibalistoibak. This enjoyable horror is also very much a tribute or open love-letter to Don Quixote de la Mancha, with whom Donald both idolises and identifies, although the dream encounters also bring to mind Gulliver's meetings with the Brobdingnagians and Lilliputians. In more than one way it is Don Quixote who saves the world.