Some way ahead of them an awkward low shape was heaving itself wretchedly along the ground, stumbling painfully slowly, half-limping, half-crawling.

It was moving so slowly that before too long they caught the creature up and could see that it was made of worn, scarred and twisted metal.

It groaned at them as they approached it, collapsing in the hot dry dust.

“So much time,” it groaned, “oh so much time. And pain as well, so much of that, and so much time to suffer it in too. One or the other on its own I could probably manage. It’s the two together that really get me down. Oh hello, you again.”

“Marvin?” said Arthur sharply, crouching down beside it. “Is that you?”

“You were always one,” groaned the aged husk of the robot, “for the super-intelligent question, weren’t you?”

“What is it?” whispered Fenchurch in alarm, crouching behind Arthur, and grasping on to his arm. “He’s sort of an old friend,” said Arthur. “I…”

“Friend!” croaked the robot pathetically. The word died away in a kind of crackle and flakes of rust fell out of its mouth. “You’ll have to excuse me while I try and remember what the word means. My memory banks are not what they were you know, and any word which falls into disuse for a few zillion years has to get shifted down into auxiliary memory back-up. Ah, here it comes.”

The robot’s battered head snapped up a bit as if in thought.

“Hmm,” he said, “what a curious concept.”

He thought a little longer.

“No,” he said at last, “don’t think I ever came across one of those. Sorry, can’t help you there.”

He scraped a knee along pathetically in the dust, an then tried to twist himself up on his misshapen elbows.

“Is there any last service you would like me to perform for you perhaps?” he asked in a kind of hollow rattle. “A piece of paper that perhaps you would like me to pick up for you? Or maybe you would like me,” he continued, “to open a door?”

His head scratched round in its rusty neck bearings and seemed to scan the distant horizon.

“Don’t seem to be any doors around at present,” he said, “but I’m sure that if we waited long enough, someone would build one. And then,” he said slowly twisting his head around to see Arthur again, “I could open it for you. I’m quite used to waiting you know.”

“Arthur,” hissed Fenchurch in his ear sharply, “you never told me of this. What have you done to this poor creature?”

“Nothing,” insisted Arthur sadly, “he’s always like this…”

“Ha!” snapped Marvin. “Ha!” he repeated. “What do you know of always? You say ‘always’ to me, who, because of the silly little errands your organic lifeforms keep on sending me through time on, am now thirty-seven times older than the Universe itself? Pick your words with a little more care,” he coughed, “and tact.”

He rasped his way through a coughing fit and resumed.

“Leave me,” he said, “go on ahead, leave me to struggle painfully on my way. My time at last has nearly come. My race is nearly run. I fully expect,” he said, feebly waving them on with a broken finger, “to come in last. It would be fitting. Here I am, brain the size…”

Between them they picked him up despite his feeble protests and insults. The metal was so hot it nearly blistered their fingers, but he weighed surprisingly little, and hung limply between their arms.

They carried him with them along the path that ran along the left of the Great Red Plain of Rars toward the encircling mountains of Quentulus Quazgar.

Arthur attempted to explain to Fenchurch, but was too often interrupted by Marvin’s dolorous cybernetic ravings.

They tried to see if they could get him some spare parts at one of the booths, but Marvin would have none of it.

“I’m all spare parts,” he droned.

“Let me be!” he groaned.

“Every part of me,” he moaned, “has been replaced at least fifty times… except…” He seemed almost imperceptibly to brighten for a moment. His head bobbed between them with the effort of memory. “Do you remember, the first time you ever met me,” he said at last to Arthur. “I had been given the intellect-stretching task of taking you up to the bridge? I mentioned to you that I had this terrible pain in all the diodes down my left side? That I had asked for them to be replaced but they never were?”

He left a longish pause before he continued. They carried him on between them, under the baking sun that hardly ever seemed to move, let alone set.

“See if you can guess,” said Marvin, when he judged that the pause had become embarrassing enough, “which parts of me were never replaced? Go on, see if you can guess.

“Ouch,” he added, “ouch, ouch, ouch, ouch, ouch.”

At last they reached the last of the little booths, set down Marvin between them and rested in the shade. Fenchurch bought some cufflinks for Russell, cufflinks that had set in them little polished pebbles which had been picked up from the Quentulus Quazgar Mountains, directly underneath the letters of fire in which was written God’s Final Message to His Creation.

Arthur flipped through a little rack of devotional tracts on the counter, little meditations on the meaning of the Message.

“Ready?” he said to Fenchurch, who nodded.

They heaved up Marvin between them.

They rounded the foot of the Quentulus Quazgar Mountains, and there was the Message written in blazing letters along the crest of the Mountain. There was a little observation vantage point with a rail built along the top of a large rock facing it, from which you could get a good view. It had a little pay-telescope for looking at the letters in detail, but no one would ever use it because the letters burned with the divine brilliance of the heavens and would, if seen through a telescope, have severely damaged the retina and optic nerve.

They gazed at God’s Final Message in wonderment, and were slowly and ineffably filled with a great sense of peace, and of final and complete understanding.

Fenchurch sighed. “Yes,” she said, “that was it.”

They had been staring at it for fully ten minutes before they became aware that Marvin, hanging between their shoulders, was in difficulties. The robot could no longer lift his head, had not read the message. They lifted his head, but he complained that his vision circuits had almost gone.

They found a coin and helped him to the telescope. He complained and insulted them, but they helped him look at each individual letter in turn, The first letter was a “w”, the second an “e”. Then there was a gap. An “a” followed, then a “p”, an “o” and an “l”.

Marvin paused for a rest.

After a few moments they resumed and let him see the “o”, the “g”, the “i”, the “s” and the “e”.

The next two words were “for” and “the”. The last one was a long one, and Marvin needed another rest before he could tackle it.

It started with an “i”, then “n” then a “c”. Next came an “o” and an “n”, followed by a “v”, an “e”, another “n” and an “i”.

After a final pause, Marvin gathered his strength for the last stretch.

He read the “e”, the “n”, the “c” and at last the final “e”, and staggered back into their arms.

“I think,” he murmured at last, from deep within his corroding rattling thorax, “I feel good about it.”

The lights went out in his eyes for absolutely the very last time ever.

Luckily, there was a stall nearby where you could rent scooters from guys with green wings.