Arthur Dent wakes up with a hangover and ponders why he drank excessively the previous night. He senses some unease but cannot recall the exact problem. He notices two yellow bulldozers outside his ordinary house in an ordinary English village. He realizes that they are there to demolish his house for a bypass construction. In an attempt to save his home, Arthur throws himself in front of the bulldozers, covered in mud.
Mr. L. Prosser, a representative from the local council, reminds Arthur that he should have known about the plans and made necessary preparations. Arthur retorts that the plans were hidden in a locked filing cabinet in a dark basement bathroom of the local planning office. Prosser insists on building the bypass without providing a clear reason.
Arthur's friend, Ford Prefect, arrives and suggests going to the pub. Unbeknownst to Arthur, Ford is not from Earth but an alien stranded on the planet. Ford convinces Prosser to stand in for Arthur and block the bulldozers while he takes Arthur to the pub. Though skeptical, Arthur reluctantly agrees, influenced by Ford's assertion that they can trust Prosser, who claims the end of the Earth is only twelve minutes away.
The entry about alcohol in the Encyclopedia Galactica, which describes it as a colorless liquid produced by fermenting sugars, with The Hitchhiker's Guide to the Galaxy's entry. The guide describes the Pan Galactic Gargle Blaster, an intoxicating drink that feels like having one's brains smashed with a golden brick wrapped in a lemon slice. The narrator mentions that The Hitchhiker's Guide sells more copies than the Encyclopedia.
Unbeknownst to most people on Earth, enormous yellow spaceships hover in the ionosphere. Ford detects the ships' signal using his "Sub-Etha Sens-O-Matic" device. He carries various extraterrestrial items in his bag, including The Hitchhiker's Guide tothe Galaxy, for which he is a reporter. Ford possesses a towel from Marks and Spencer, which the guide describes as having great practical value. Ford is disappointed that Arthur doesn't have a towel and struggles to convince him that the world is about to end. They hear loud noises outside the pub, and Ford assures Arthur that it's just his house being demolished. Arthur rushes out in distress, and the bartender, sensing Ford's distress signal, announces last orders.
Ford finds Arthur near the wreckage of his house and points out the ominous yellow objects hovering in the sky. Ford realizes that the intergalactic signal he detected came from the Vogons, a race of aliens. Ford takes solace in having his towel. The Vogons announce that Earth is scheduled for demolition due to the construction of a hyperspatial express route. They scold the Earthlings for their panic, claiming that the plans were on display for fifty Earth years. The Vogons proceed with the demolition.
Zaphod Beeblebrox, the President of the Imperial Galactic Government, is on Damogran to christen the newly-built ship, the Heart of Gold. He enjoys the attention and makes a dramatic entrance by floating on a sofaencased in a bubble. With his two heads and three arms, Zaphod stands out as uniquely striking. Trillian, his casual girlfriend, is unimpressed by his theatrics, having grown tired of his attention-seeking behavior.
Vogon ship, revealing that Vogons are an underdeveloped species who depleted their planet's resources before becoming bureaucratic emissaries. It is noted that Vogons despise hitchhikers.
Meanwhile, Arthur and Ford find themselves on the Vogon ship, in the company of the Dentrassis, who serve as cooks and enjoy annoying the Vogons. They are surprised by the ship's poor condition when the lights come on, but Ford explains that it's a working ship. Ford gives Arthur The Hitchhiker's Guide to the Galaxy, an electronic book, to learn more about the Vogons. The entry warns against letting a Vogon read poetry to you.
Ford informs Arthur that they were rescued just in time as Earth has been demolished. Ford appears oblivious to Arthur's distress and advises himnot to panic, echoing the advice on the book's cover. Suddenly, the loudspeakers come alive, emitting rough howling noises. Ford places a small yellow fish in Arthur's ear, allowing him to understand the Vogon message being transmitted.
The Vogon captain warns his hitchhiking captives that they will be captured soon and brought before him. He plans to read them some of his poetry before throwing them out of the airlock. Ford has Arthur read about the Babel fish, the creature lodged in his ear that allows him to understand the Vogon language.
Arthur reflects on the recent events, still in shock from the destruction of Earth and saddened by the loss of things like Humphrey Bogart movies and McDonald's. He asks Ford for The Hitchhiker's Guide to the Galaxy again, wanting to read the entry about Earth. Surprisingly, it is brief and dismissive, stating that Earth is "harmless." This upsets Arthur, and Ford suggests updating the entry to "mostly harmless" based on his years of research. They hear footsteps approaching - the Vogons have found them.
Prostetnic Vogon Jeltz insists on subjecting his captives to his poetry, infamous as the third worst in the Universe. Arthur and Ford are secured in Poetry Appreciation chairs to endure the painful experience. The poetry causes them to scream and groan in agony. However, when the Vogon asks for compliments, Arthur surprises Ford by saying he actually liked it. They hope that flattering the Vogon will spare them from being
ejected from the airlock, but their plan fails.
A junior guard takes them to their fate, seemingly enjoying shouting at them. Ford tries to appeal to the guard's sympathy by suggesting that his job deprives him of the enriching experiences of culture and art. The guard briefly considers this but ultimately values job security and the satisfaction of shouting at people. He forcefully pushes Arthur and Ford into the outer airlock. Arthur mourns the fact that the only remaining mention of Earth will be the words "mostly harmless" from The Hitchhiker's Guide. The airlock hatch opens, and they are expelled into the vastness of outer space.
Arthur and Ford find themselves floating in space after being expelled from the airlock. The narrator provides an excerpt from The Hitchhiker's Guide to the Galaxy, emphasizing the immense size of space and the astronomical odds of being rescued. Remarkably, the numerical odds correspond to a telephonenumber that Arthur once encountered on Earth while meeting a girl. Against all odds, Arthur and Ford are suddenly rescued.
During their rescue, a hole opens up in the universe, leading to a series of improbable events. Balloons and hats rain down on the universe, while a starving tribe in another galaxy receives over two hundred thousand fried eggs. Arthur and Ford are caught in the grip of "vicious storms of unreason" and undergo unsettling transformations. Arthur witnesses his arm drifting away, and Ford gradually transforms into a penguin. Eventually, a soothing voice over the intercom welcomes them to the Starship Heart of Gold, assuring them that normalcy will be restored. However, before that, a swarm of monkeys wants them to review their script of Hamlet.
The Infinite Improbability Drive is introduced as a revolutionary
method of crossing vast distances in space instantaneously. Its invention was thought to be virtually impossible, but a student managed to develop it by considering the concept of "finite improbability." The student creates a generator, feeds it a cup of hot tea, and successfully demonstrates its capabilities. The student receives recognition and awards for the invention but is then attacked by a horde of physicists.
Zaphod Beeblebrox and Trillian are piloting the Heart of Gold while the probability numbers return to normal ranges. Zaphod is unhappy about the hitchhikers being picked up, as he is on the run for stealing the ship and wants to avoid intergalactic law enforcement. Trillian reveals that she did not pick up the hitchhikers - the ship made the decision autonomously.
Zaphod instructs Marvin, the onboard android, to fetch Arthur and Ford. Marvin, who is constantly depressed and believes life is meaningless, reluctantly carries out the task. The Guide explains that the Sirius Cybernetics Corporation designed their robots with specific personalities, much to the annoyance of those who have to interact with them. Marvin complains about life while informing Arthur and Ford that the ship has been stolen by Zaphod Beeblebrox, leaving Ford astonished.
Zaphod listens to the sub-etha radio bands for news about himself, while Trillian finds it suspicious that she was picked up by Zaphod in the same sector of space. Calculating the improbability of this coincidence results in an irrational number with significance in Improbability Physics, signifying its near-impossibility.
Arthur and Ford follow Marvin to the bridge of the spaceship, where they encounter Zaphod Beeblebrox. To Arthur's surprise, he believes he has met Zaphod before, when he was known as "Phil" at a party in Islington. At that party, Zaphod left with a woman whom Arthur was
interested in, leaving him feeling resentful. This revelation infuriates Arthur, who is now face-to-face with the person who left him stranded on Earth.
Ford, on the other hand, is astonished because Arthur not only knows Zaphod but also recognizes Trillian, who is standing with Zaphod on the bridge. Trillian is the same young woman who had left the party with Zaphod. The improbable coincidence of all these connections leaves Arthur and Ford in disbelief as the situation becomes increasingly bizarre.
The group contemplates the reason for their gathering. Trillian struggles to sleep, distressed by the destruction of Earth and the fact that only she, Arthur, and two white mice remain from the planet. Zaphod is unable to sleep due to the implausibility of his own actions and the circumstances that brought Arthur and Ford into his life. Ford, on the other hand, is unable to sleep out of excitement for being back in the universe with his cousin. Arthur sleeps deeply, exhausted from his recent adventures.
The following morning, Trillian informs Zaphod that she believes they have found what he has been searching for.
The Hitchhiker's Guide to the Galaxy, detailing the planet of Magrathea. It was renowned for creating custom-made planets for the wealthiest individuals during the Empire's golden age. The immense success of Magrathea resulted in extreme wealth, leading to the rest of the Empire experiencing poverty. As a result, Magrathea faded into legend, and few believe in its existence anymore.
Arthur enters the bridge where Zaphod and Ford are engaged in an argument about the reality of Magrathea. Ford dismisses it as a fairy tale parents tell their children to encourage them to become economists.
Despite their disagreement, they all agree that the planet below, which appears beautiful and ancient, must be Magrathea. Arthur realizes that something is missing: tea. The narrator confirms that the planet is indeed Magrathea and assures the readers that nobody will be killed in the upcoming events, although someone will sustain a bruise to the arm.
Arthur sets off in search of tea, which he obtains from a Nutri-Matic machine. The tea is described as almost, but not quite, entirely unlike tea. The revitalizing effects of the tea prompt Arthur to join the conversation about their venture onto the planet. He expresses concern aboutsafety, and Zaphod reassures him by claiming it to be a ghost planet. However, their reassurance is interrupted when they hear a voice transmitted to the ship, politely asking them to leave. As the ship continues to approach the planet, the voice becomes increasingly threatening, mentioning guided missiles converging on the ship. Evidently, Magrathea does not welcome visitors.
Zaphod attempts to take control of the ship to evade the missiles, but his lack of flying expertise becomes apparent. He steers the ship directly into the path of the approaching missiles, seemingly dooming the group to certain death. They are thrown against the cabin wall, unable to reach the controls. At that moment, Arthur suggests activating the Infinite Improbability Drive. Being close to the control panel, he activates it, resulting in a mind-boggling explosion of noise and light.
The crew of the Heart of Gold is saved by the Infinite Improbability Drive. The ship's interior has been beautifully redesigned to resemble a classical conservatory, complete with marble statues, a spiral staircase, and a garden surrounding the control panel. The danger of the approaching missiles has been averted as they have transformed into a surprised-looking whale and a bowl of petunias. The crew is now safe.
The chapter then focuses on the thoughts of the whale as it plummets towards the planet's surface. It contemplates the purpose of its existence, tries to name different body parts and sensations, and
wonders if the impending impact will be friendly. Eventually, there is a wet thud, and silence follows. In contrast, the bowl of petunias groans, exclaiming, "Oh no, not again."
The Heart of Gold has landed, and the crew, including the android, prepares to disembark. Trillian realizes that her mice have escaped, although this seemingly minor issue would have been taken more seriously if the crew had a better understanding of Earth's intellectual hierarchy. The computer, now modified to be more anxious, reluctantly allows the crew to exit. Unbeknownst to Zaphod and the others, the computer opens the hatch again unexpectedly.
The surface of Magrathea is described as dullish brown and gray, devoid of any notable features. The crew finds themselves walking amidst splattered whalemeat, a result of the whale's crash landing. However, the impact has also created a fissure that leads to underground tunnels, where the Magratheans were rumored to have lived. Zaphod assigns Arthur and Marvin as guards for the openingwhile he, Ford, and Trillian descend into the tunnels.
Ford questions Zaphod about the purpose of their visit, and Zaphod admits that he often wonders why he does the things he does. He confesses to undergoing brain scans and discovering a section in the middle of his brain that is connected to Ford's brain alone. The culprit left initials burned into the cauterized synapses, matching Zaphod's initials. Before Zaphod can reveal more, gas begins to fill their lungs, causing them to pass out.
While onboard the spaceship, Arthur begins to read random passages from The Hitchhiker's Guide to the Galaxy. In one of the entries, he learns about a young man named Veet Voojagig, who becomes obsessed with finding a planet inhabited by ballpoint pens, hoping to uncover the
mystery of his lost pens. Surprisingly, Voojagig claims that he did find such a planet, but when an expedition is sent to verify his discovery, they only find a small asteroid instead.
Despite the disappointment, Voojagig becomes wealthy due to an unexpected turn of events. His friend, Zaphod Beeblebrox, starts a highly profitable secondhand ballpoint business, mysteriously paying Voojagig large sums each year.
Feeling exhausted from reading, Arthur tries to strike up a conversation with Marvin the robot, but Marvin rejects every attempt at communication. Frustrated, Arthur decides to take a walk. During his walk, he encounters an old man, setting the stage for a new development in the story.
The old man, Slartibartfast, assures Arthur and his friends that they won't be harmed. He explains that the missiles were launched by an ancient automated system and clarifies that the inhabitants of Magrathea are not dead but have been in a state of suspended animation, waiting for the economic conditions of the galaxy to improve. Slartibartfast insists that Arthur accompanies him deep into the planet, leaving Marvin behind. He reveals his name to be Slartibartfast, to which Arthur responds with disbelief.
Dolphins are actually more intelligent than humans, contrary to common belief. The dolphins had tried to warn humans about the impending destruction of Earth, but their efforts were mistaken as playful behavior. Consequently, the dolphins used their own means to escape the planet's annihilation. The narrator hints that there is another species even more intelligent than dolphins.
Slartibartfast takes Arthur on a fast aircar ride deep into Magrathea. He acknowledges that he knows Arthur is an Earthling but doesn't
disclose how he knows. As they reach the "factory floor" of Magrathea's planet-building operation, Arthur is overwhelmed by the vastness of the enterprise. He is astounded when he sees a planet resembling Earth under construction. Slartibartfast explains that they are recreating Earth from the originalblueprints. Earth, it turns out, was a designer planet commissioned by highly-evolved mice for a specific purpose. Unfortunately, it was destroyed just moments before its intended purpose was fulfilled. The Magratheans are now rebuilding it, as Earth serves as an organic computer running a ten-million-year research program. Arthur finds it difficult to comprehend this revelation.
Slartibartfast proceeds to recount the origin of the commission for "Earth." Millions of years ago, a species deeply interested in existential questions decided to construct a massive computer, known as Deep Thought, to find the answer to the ultimate question of life, the universe, and everything. Controversy arises as influential philosophers fear losing their importance if the computer provides the answer. Deep Thought explains that it will take approximately seven and a half million years to find the answer, allowing philosophers to profit from promoting their theories in the meantime. The computer is left to carry out its monumental task.
Arthur interrupts Slartibartfast's story and expresses his confusion about the connection between the Earth he knew and the pandimensional mice. Slartibartfast patiently explains that this is only the first half of the story and offers to take Arthur on a tour of the new Earth that is being built. Sadly, Arthur declines the offer, stating that it wouldn't be the same.
Slartibartfast leads Arthur to his cluttered office, filled with books and maps. He provides Arthur with a headset that will allow him to witness
the second half of the story through a recording. The moment arrives when Deep Thought, the great computer, is set to reveal the answer to the ultimate question of life, the universe, and everything. Amidst much anticipation, Deep Thought slowly awakens and confidently announces, "Forty-two."
The answer of "forty-two" causes an immediate uproar among the crowd. Deep Thought calmly explains that the problem lies in the fact that they never truly knew what the question was. This creates further chaos, leading the people to ask Deep Thought to calculate the question. Deep Thought admits its incapacity to do so but suggests the construction of a new, even more powerful computer capable of determining the question. This new computer is named "the Earth" by Deep Thought.
Trillian and Ford wake up Zaphod, who is still recovering from the effects of the gas. They find themselves in a simulated catalog of what Magrathea has to offer. Zaphodis particularly excited about a planet made entirely of solid gold. The conversation turns back to Zaphod's decision to sever parts of his own brain. He recalls his association with Yooden Vranx, an impresario who told him about the Heart of Gold and suggested stealing it. Zaphod's bid for the presidency was merely a ploy to gain access to the unveiling event and steal the ship with its Infinite Improbability Drive. However, he still does not know the reason behind his desire to steal the ship. Slartibartfast appears and informs them that they are about to meet the mice.
Slartibartfast fills in the missing information for Zaphod, Trillian, Ford, and Arthur regarding the original purpose of the custom-designed planet Earth. Arthur bitterly adds that the planet was destroyed just moments before the calculations were complete. Slartibartfast expresses his own
disappointment as his fjord designs in Norway, for which he won an award, are now gone. He informs them that they are soon to meet the mice, an event he considers to be the third most improbable in history.
Digression on the consequences of careless talk, mentioning how Arthur's joke in the previous chapter caused a wormhole to open up and incited a battle on another world. The battle raged for thousands of years until it was discovered that Arthur's words were from an Earthling. They spent several thousand more years tracking down the source, only to have their fleet accidentally swallowed by a small dog on Earth.
The mice, Benjy and Frankie, welcome the group to lunch and reveal that they no longer require the rebuilt planet Earth. They explain their weariness with the philosophical endeavor of finding the answer to life, the universe, and everything, as well as the subsequent search for the question. They now believe that Arthur's brain contains the necessary data, offering to buy it and replace it with an electronic model. Arthur refuses and a chase ensues, with Arthur and the others being cornered by men with ominous medical equipment. The scene is interrupted by a loud alarm.
The transportation devices used by the mice lie smashed on the floor, and their henchmen are unconscious. Arthur and his companions have successfully escaped. The mice discuss their next move and decide to create a fake question to match the answer "42." They settle on "How many roads must aman walk down?" and plan to profit from it on the lecture circuit. Meanwhile, the group is being pursued by cops who are after Zaphod for stealing the Heart of Gold. A conversation ensues where the disillusioned cops express their desire for more enjoyable activities. However, they resume shooting at the group.
Suddenly, the shooting stops, and a quiet descends. Uncertain if it's a
trap, Ford cautiously goes to investigate the cops. He discovers that they are all dead, their life support systems having mysteriously failed. The group decides to escape using Slartibartfast's aircar, which Arthur recognizes. There is a simple note with instructions on how to pilot the vehicle, suggesting the best button to press.
As they rush back to the Heart of Gold, Ford is still contemplating the mysterious nature of their recent escape. The rest of the group, however, shows no curiosity about what just happened and quickly boards the ship. They are taken aback to find Marvin lying face down in the cold dust, waiting for them. Marvin reveals that everyone hates him, even the policecraft he attempted to communicate with despises him. When Ford inquires about the outcome of the exchange with the policecraft, Marvin simply replies that "It committed suicide," refusing to elaborate further on the matter.
The Heart of Gold continues its journey, with Zaphod drinking a Pan Galactic Gargle Blaster while Trillian and Ford engage in thoughtful conversation. Arthur decides to take The Hitchhiker's Guide to the Galaxy to bed, acknowledging the need to learn as much as possible about the Universe. He reads an entry mentioning lunch when Zaphod contacts him via intercom, asking if he is hungry. Arthur responds affirmatively, so Zaphod steers the ship towards the Restaurant at the End of the Universe.