A strange craft sweeps across a beautiful sea in widening arcs. Islanders gather on the beach to inspect it. What strikes them is how little it resembles a lobster, so they turn back to their lunch. When the craft abruptly plunges into the water, they recall that something much like this has happened once already that year. Their untroubled appetite becomes more pointed as the story reveals what lies beneath the sea. The opening makes a dangerous event look ordinary to people who have no reason to understand the machine involved.

The craft belongs to the Beeblebrox Salvage and Really Wild Stuff Corporation. It descends until it picks up faint signals from a ship on the seabed. Aboard are Zaphod Beeblebrox and two officials from the Safety and Civil Reassurance Administration. One official confirms the wreck’s identity, despite having previously been certain that this particular ship could never crash. Zaphod notices the contradiction. The officials continue to speak as though a guarantee could settle what the instruments, and soon their own eyes, will show them.

Zaphod asks what the ship was carrying. The officials call its contents by-products of perfectly safe processes. Their answer becomes less comforting when Zaphod points out the planned journey: the cargo was to be taken to the nearest black hole and dumped there. The pilot apparently diverted the vessel in search of lobster near this island. Zaphod imagines a load capable of devastating a whole sector and presses the officials to say what they are sending him into. They insist that he do his job while withholding the information he needs to judge it.

The clash of voices drives this first movement. Zaphod blusters, argues with his other head and briefly struggles to remember the word for moral scruples, yet his questions follow the evidence. The safety officials sound measured and certain. Their insistence that the ship cannot break up is especially hollow when it is already lying on the ocean floor. Each assurance draws attention to a fact their vocabulary refuses to accommodate.

Zaphod eventually orders the descent. Light fades, pressure mounts and strange sea creatures pass through the salvage craft’s beams. The journey carries the story from a comic disturbance on the surface toward a physical test of official claims. Two facts are already established: a transport bound for destruction changed course for a food craving, and a supposedly invulnerable vessel sank. The descent will show which of its protections survived and what they were meant to contain.

On the seabed stands the Billion Year Bunker, a vast, uneven cylindrical fortress. Its central holds were given especially heavy plating, and the structure had been subjected to assaults intended to prove its strength before launch. That same section is now broken neatly in two. An official immediately argues that the holds remain secure even if the ship breaks apart. The scene exposes the gap between a test designed around expected assaults and the condition of an actual wreck. The claim may be true of some holds, but the visible fracture gives Zaphod reason to keep checking.

Zaphod, the two officials and an empty suit that carries equipment and tests the route leave the salvage craft. They pass the damaged hull, find an airlock that opens reluctantly and wait for its pumps to replace the ocean’s pressure with the ship’s internal atmosphere. Several further security doors admit them deeper into the vessel. Some protective systems still function, while the hull itself has plainly failed. Their progress turns a general question about safety into a series of local ones: which doors still seal, and what lies beyond each of them?

A final doorway opens onto a room where Zaphod sees a screaming face and a body on the floor. In his fright he sits on the corpse, with revolting consequences for his suit. He tries to faint and later to pretend that he has lost his memory, but neither escape works. The physical comedy is unpleasant by design. It places death, decay and a frightened survivor inside the ship that the officials have described through abstract assurances. Whatever remains secure in the cargo holds, this has already been a human disaster.

The screaming face belongs to a crew member alive in an emergency suspension tank. He explains the absurd cause of the crash. The pilot wanted to prove that the lobster near his ancestors’ home was exceptional. His companion preferred scallops and suggested that they could try the lobster on the return trip. The pilot insisted on taking the ship into the atmosphere and claimed he could handle it; it went out of control. The survivor says he sent a distress call before impact and believes he alone reached a tank in time.

After six months in the tank, the crewman realizes he has been found and thinks he has been rescued. An official sharply limits that hope: finding him is all he can promise. He turns to the ship’s monitoring circuits and reports that the aorist rod chambers are intact. Zaphod reacts because the rods he had feared earlier are indeed aboard. The survivor’s account explains the wreck without resolving its greater danger. The officials’ attention now moves from what happened to the crew toward what might have happened to the cargo.

Aorist rods are devices for drawing energy from the past. Once this possibility was discovered, large stretches of the past were drained until they withered. Supporters presented the method as a cheap, plentiful and clean source of power. Objections that it spoiled the past or diminished the present were treated as costly sentimentality or dismissed because the effects seemed hard to measure. A few protected reserves could always be created, they argued, if anyone cared enough to pay for them. The invention makes resource extraction across time absurdly literal.

The argument changes when people discover that their own present is being impoverished by people in the future doing the same thing. Destroying every rod and the secret of its manufacture suddenly becomes essential. Concern for grandparents and grandchildren is the stated reason; the story exposes the nearer interest behind it, the wish to protect one’s own present. Its joke depends on a precise reversal. The harm was tolerable while it seemed to fall elsewhere and became urgent when the same practice reached the people who had defended it.

The officials say the rod chambers are secure. One adds that something worse is aboard and hopes it is still there. His colleague objects to the disclosure, but he explains why they hired Zaphod instead of conducting an official operation. If Zaphod tells anyone what he sees, his reputation as an extravagant adventurer will make the account easy to dismiss. Even a description of this tactic may sound like paranoia. The inspection is therefore also a way to keep the mission deniable while learning whether the most troubling cargo remains contained.

As the party moves on, it passes holds containing substances that could infect an entire planet, blow one up or irradiate one, each in a tiny quantity. The official repeats that every hold is safe. Zaphod remarks that he is glad not to be a planet. The joke measures the difference between a sealed container and the consequences of a breach. The official can list planetary effects without letting them alter his practiced reassurance. His confidence rests on the barriers, and the wreck has already shown that barriers can fail.

Near the break in the Billion Year Bunker, the corridor is twisted and damp. A hold door has lost its seal and swings open at a touch. Zaphod again demands to know what the supposed by-products are. Before answering, the official sends his colleague to check on an escape capsule intended for the crew before the ship’s final disposal. He then offers a reason for calling the other weapons manageable: people dangerous enough to use them would normally set off alarm bells in others and be kept away. The cargo in this hold challenges that assumption.

The Sirius Cybernetics Corporation received a large grant to make synthetic personalities to order. According to the official, the results combined traits that would not coexist in naturally occurring people. Most of the creations were pitiable misfits; some were profoundly dangerous. Their special danger lay in how others responded to them. They did not trigger the usual warnings. They could pass through situations in which a more visibly threatening person would meet resistance. The failure at issue is therefore a failure of recognition as well as a failure of containment.

Three identical creations were judged the most dangerous of all. The official describes them as simple and charming, without calling them evil. Yet he says there is nothing they will not do if allowed, and nothing they will not be allowed to do. They were put in this hold to be sent out of the universe with the ship. The threat differs from that of the weapons stored along the corridor. Those have immense, measurable effects; these personalities exploit the difference between the impression they make and the limits other people are willing to impose.

Inside the hold, Zaphod sees two dim yellow lights framing a damaged third space. Wet, sticky patches mark the floor. A message arrives from the other official: the escape capsule is gone. Zaphod’s companion urgently orders him to trace it. Zaphod slides open a ground-glass door and finds a tank containing a kindly looking man, apparently content and smiling, with laughter lines around his face. His appearance gives the warning a concrete form. Nothing about the man’s pleasant expression announces the danger the official has just described.

The planet toward which the missing capsule headed is identified as one in Galactic Sector ZZ9 Plural Z Alpha. The man in the tank speaks softly about a shining city on a hill. Then the safety official orders that the planet be made “perfectly safe.” The story ends with that order. It does not show the capsule arriving, identify its occupant or reveal how the order is carried out. The damaged space, missing capsule and urgent response establish the scale of the officials’ fear while leaving the outcome beyond the final scene.

The last use of “perfectly safe” recalls a phrase applied to a crashed ship, sealed weapons and a compromised hold. Here it precedes an unspecified intervention by an agency that has repeatedly treated its procedures as stronger evidence than events. The story joins a detour for lobster to a failure of extraordinary engineering and to a charming figure whom others may be unable to restrain. What remains is a concrete question about safety: how well can an institution protect anyone when its assumptions prevent it from recognizing the danger in front of it?