The topic was a contest or competition. No further hints of clues were provided. I'd been reading about the Apollo moon landing missions, and I remembered that the astronauts often did something frivolous on their moon walks. Then I thought about Alan Shepard who was the only one of the original Mercury Seven astronauts to reach the moon. Those three ideas coalesced in my head and the story pretty much wrote itself...

Fra Mauro is home to the best golf course on the moon. That’s not a difficult title to win – Fra Mauro is, in fact, the only golf course on the moon. It was built by the eccentric American billionaire Elon Musk in 2048. He claimed that since Alan Shepard, the commander of the Apollo 14 mission, had hit two golf balls in the Fra Mauro crater, it was clearly the very best place to build a lunar golf course. So that’s exactly what he did.

While the golf course was being built, the contractors had found one of Alan Shepherd’s original golf balls. We had it carefully mounted in a lucite slab and these days it sits proudly in a display case just inside the entrance to the club house. The second golf ball has never been found.

In 2071, to commemorate the centenary of the Apollo 14 landing, we decided to hold a prestigious tournament. People would come from all over the solar system to play or to watch. The final round of the match was due to be played on the 6th of February, exactly one hundred years to the day since Alan Shepherd first turned Fra Mauro into a driving range.

I was nominated to be the caddy for Peter Nicklaus, one of the players from the Martian colony. Peter’s great-grandfather had been a famous professional golfer back on Earth in the twentieth century and I was keen to see if Peter had inherited the golfing gene. We met in the club house just before Peter was due to play his first round. I found him admiring Alan Shepard’s golf ball and I hurried over to introduce myself. "Hello, Peter," I said. "I’m your caddy, John Tennant."

He turned round and smiled at me and we shook hands. "Hello John," he said. "It’s good to meet you. What can you tell me about the playing conditions? This is my first time playing at Fra Mauro."

"You might find things a bit awkward at first," I said. "You’ll be dressed in a pressure suit, of course, and that will put a bit of a damper on your swing. But the suit is a lot more flexible than Alan Shepard’s was so you will find it a lot easier to hit the ball than he did."

"I’ve worn pressure suits on some of the Martian courses," he said. "So I don’t expect that will be a problem. Actually, it might give me a bit of an advantage over some of the players from Earth. I imagine a lot of them will never have worn a pressure suit before."

"You’d be surprised how many of them have," I said. "A lot of them have played at Fra Mauro before."

"Oh well," he said. "Never mind. Let’s go and play our first round so I can get a feel for the course."

We suited up and tested our radios to make sure that we would be able to speak to each other as we went from hole to hole. I loaded the golf clubs into a caddy cart. We climbed into the front seats and I drove out of the airlock and headed towards the first fairway. Peter set his ball firmly in the tee and I handed him a suitable club. He looked at it suspiciously. "This isn’t what I’d normally use to tee off," he said. "Are you sure it’s the right one?"

"Trust me," I said. "This is the moon. Conditions are very different here. This club will be fine."

He gave me the benefit of the doubt and took the club. He swished it back and forth a couple of times to get the feel of it, then he addressed the ball. He hit it cleanly and it soared high into the black sky. All the golf balls being used in the tournament had a built in GPS tracker so that we’d always be able to find them no matter how awkwardly the player sliced the ball. After all, there’s no point in littering the moon with lost golf balls. Alan Shepard did quite enough of that, thank you very much.

But we didn’t need the tracker this time. The ball flew straight down the middle and plopped itself onto the green just a few metres from the hole. Green is a euphemism of course. There isn’t any grass on the moon. All that the greenkeepers do is remove the rocks and brush the surface smooth. A small puff of moon dust flew up as the ball landed, but it quickly fell back. "Good shot," I said. "Nicely played."

"Thank you." said Peter. He sounded astonished. "I’ve never hit a ball that distance before. It’s gone three times as far as it would have gone on Earth and twice as far as it would go on Mars."

"That’s the benefit of the really low gravity here," I said. "Because of it, the par for each hole is ridiculously tiny compared to similar holes elsewhere. This one is only a par two."

"Goodness," said Peter, impressed. "I’d better putt the ball very carefully then. I don’t want a bogey on my very first hole!"

Peter turned out to be a very good player. I’m sure his great-grandfather would have approved. He finished the round one under par, which was very respectable indeed. I was looking forward to the next few days.

* * * *

Finally the 6th February arrived, the last day of the tournament. By this time I was starting to worry. Peter had played such perfect rounds that I hadn’t had any chance to set up the surprise I had planned for him. But today, on the fifth hole, he sliced the ball very badly and it soared off the course, heading into the wild black yonder to land who knew where. For the first time since the tournament began, I had to use the GPS tracker to find it. "Stay here," I said to Peter. "I’ll call you over when I’ve pin pointed exactly where it is."

"OK," he said agreeably.

I shuffled off into the lunar desolation being careful not to trip over the slippery rocks that jutted out of the regolith. The ball wasn’t hard to find. Fortunately it was lying on a relatively flat and smooth patch of ground. Peter should have no difficulty reaching the hole from here. I took another golf ball out of a pouch on my suit and I put it in the shadow cast by a nearby rock. The ball had been carefully aged, the surface darkened, cracked and pitted as if from a century of exposure to radiation and micrometeorite impacts. "I’ve found it," I called to Peter. "And you’ll never guess what else I’ve found as well!"

Curious, Peter came loping over to see what I meant. I pointed out the old golf ball. "Look at that," I said. "I’m pretty sure that’s Alan Shepard’s second golf ball. The one that was never found. What an amazing souvenir for you to take back home!"

Peter bent down and picked it up. He examined it carefully. "It certainly looks like it might be the second ball," he said. "But I can’t keep it. It really should be put on display with the other one."

Silently I cursed his honesty. "No," I said, "put it in your pouch and take it with you when you leave. Imagine how good it will feel to own such a piece of golfing history. Of course you won’t be able to tell anyone you’ve got it. You’ll have to keep it secret or they’ll take it away from you to show it to the world."

We argued the point back and forth for a while, but eventually I managed to persuade him that he really should keep the golf ball, if only for the sense of history. He put it in his suit pouch and we carried on with the game. The rest of the tournament was uneventful and Peter finished the day, and the tournament, in second place. His great-grandfather would have been proud of him.

We had a huge party in the club house afterwards and the next day all the hungover caddies said goodbye to all the hungover players as they went back to wherever it was that they had come from. Every single one of the players had Alan Shepard’s second golf ball packed securely and secretly away in their luggage. Sometimes I think that there might be more second Alan Shepard golf balls in the world than there are fragments of the true cross.

The caddies had all been carefully coached and rehearsed in their role. They had successfully guided each player to their golf ball discovery, and made sure that everyone knew how important it was to keep that discovery secret. "Do you think the word will ever get out?" someone asked me as we watched the players trudge into the cart that would take them to the space port.

"Of course it will," I said. "Three people can keep a secret only if two of them are dead. We’ll be hearing all about it in the news feeds very soon, I would imagine."

"Quite the cynic, aren’t you?" he said.

We’d spent a lot of time preparing the golf balls to make them look convincing. I thought we’d done a very good job. They looked exactly like the real second golf ball, the one I had stowed away in my room, the one I’d found shortly after I’d started working at Fra Mauro, the one I’d never told anybody about.

I’m certain it’s the real one...