It details the exploits of the hero of a number of his stories, Ijon Tichy, as he visits the Eighth World Futurological Congress at a Hilton Hotel in Costa Rica.

Lem is fiercely satirical from the start, and absurdities abound at the Hilton with its guaranteed "BOMB-FREE" rooms and the extravagances of Tichy's suite, which include a palm grove and an "all-girl orchestra [that] played Bach while performing a cleverly choreographed striptease".

Events spiral out of control at the Hilton, which was already so chaotic that charred corpses from bombing attacks would be covered with tarps where they lay while guests went about their business.

Tichy is evacuated from the scene by the military: first he escapes by jetpack, only to realise he is hallucinating (falling in the sewer water to find he never left).

This time when he wakes up, he finds that he has been transplanted into the body of an overweight, red-haired man, however this too is an illusion (again, broken when Tichy falls into the sewer water).

Tichy gets involved with a woman, and during an argument, she deliberately takes a drug called recriminol to make her more combative, which prolongs the tiff.

Trottelreiner explains that the Narcotics and hallucinogens that Tichy is tired of are trifles compared to "mascons", which are so powerful that they mask whole swaths of reality.

With his first sniff of up'n'at'm, Tichy watches as the gilded surroundings of the five-star restaurant they are in evaporates into a dingy concrete bunker, and his stuffed pheasant turns into "the most unappetizing gray-brown gruel, which stuck in globs to my tin — no longer silver — fork".

In a state of panic, Tichy realizes that he is "no longer safely inside the illusion, but shipwrecked in reality", and he desperately seeks the seat of power.

They plummet to the earth, but instead of colliding with the frozen ground, Tichy splashes into the black, stinking waters of the sewer beneath the Costa Rica Hilton, revealing that his suspicions were right all along: the whole future world he experienced was an illusion.

The title of the book was used for one episode of the German TV show Ijon Tichy: Raumpilot, which itself was rather based on the story "The Eighth Voyage" from Lem's The Star Diaries.