After being stranded on pre-historic Earth after the events in The Restaurant at the End of the Universe, Arthur Dent is met by his old friend Ford Prefect, who drags him into a space-time eddy, represented by an anachronistic sofa.

Shortly after they arrive, a squad of robots land in a spaceship in the middle of the field and attack the assembled crowd, stealing the Ashes before departing.

Another spaceship arrives, the Starship Bistromath, helmed by Slartibartfast, who discovers he is too late to stop the theft and requests Arthur and Ford's help.

Reverse engineering the vessel, they explored past the dust cloud and saw the rest of the Universe, immediately taking a disliking to it and deciding that it must be destroyed.

They built a fleet of ships and robots to attack the rest of the Universe in a brutal onslaught known as the Krikkit Wars, but were eventually defeated.

Arthur manages to escape unharmed, partially due to learning how to fly after falling and missing the ground while catching sight of a bag he had lost at a Greek airport years before.

Meanwhile, the Krikkit robots steal the last two pieces, the Infinite Improbability Drive core from the spaceship Heart of Gold and a peg leg used by Marvin the Paranoid Android.

The Bistromath arrives too late to stop the robots from opening the Gate, so its occupants transport to the planet to attempt to negotiate with the Krikkit people.

To their surprise, they find that the people seem to lack any desire to continue the war, and are directed to the robot and spaceship facilities in orbit about the planet.

Hactar reveals that he spent eons creating the spaceship that crashed on Krikkit to inspire their xenophobia and incite them to go to war, also influencing their thoughts.

However, during his run-up, Arthur suddenly realizes that the ball was created and placed in his bag by Hactar and is actually the working version of the cosmic-supernova-bomb, and that the defender of the wicket is one of the Krikkit robots, ready to detonate the bomb once thrown.

Arthur trips, misses the ground, and flies over the pitch, allowing him to throw the bomb safely aside and behead the robot with its own bat.

Some time earlier, he had been reporting on a court case in which a witness named Prak was inadvertently given an overdose of a truth drug.