I put on my boots, locked up, and set off once more in the direction of the mad beehive.

Once there, I left my rucksack in the shade of the emptied Langstroth box and walked due east, going nearly half a mile before turning back to where I had started. I walked slowly, searching the ground, the air, the surroundings in general, to see what was different about this particular hive.

Back and forth I went, my senses open to that one lonely patch of downland. I climbed over stone walls, poked about in holes looking for poison bait, wrote down the name of every plant in the vicinity, the presence of sheep, the lack of trees.

After three hours, the sun was scorching and I was thoroughly fed up with the entire puzzle. I drained my last drop of warm lemonade and tried to put my thoughts in order.

There was nothing I could see that set this hive apart from the others. Except that it was, in fact, apart, this being the furthest of Holmes' hives. As yesterday's blistered palms could well testify.

Plenty of food-the honey in the frames had told me that. A fertile queen-any number of fertile queens. So what was it? Why dislike this place? What had so infected the community with alarm and despondency that they had deserted their brood?

With a sigh of resignation at my own unwillingness to let go of the conundrum, I got down on my hands and knees at the front of the hive and picked through the grass with my fingertips.

There were dead bees there, of course-workers only live a few weeks, and a sentimental burial is not in the hive's interest. Still, I dutifully gathered up those that were not dried to a husk, taking care not to impale myself on the stingers, and folded them into a sheet of paper. Perhaps examination under a microscope would reveal a parasite.

When I was finished, I climbed onto the wall and gazed at the slopes running down to the Channel. The water was blue today beneath the summer's sun; I counted twenty-three vessels, from light sail-boat to heavy steamer, in the patch immediately before me.

Not so this piece of hillside. Even in August, this was away from the shoes of long-distance ramblers and day-tourists alike. The nearest house was almost a mile away, the grassland was broken by nothing larger than gorse bushes.

A small and tentative idea, born of the loneliness of the place and three days of my own solitude, crept into the side of my mind. I looked speculatively down at the packet of bees.

Then I hopped down from the wall and went back to the house. I spent some time with the more scientific manuals on bees, until I was certain that they were all workers, then went to the honey shed to retrieve one of the frames containing queen cells. I wrapped it with care, laid it in my bicycle basket, and set off for Jevington, where Mr Miranker's letter had come from.

A woman tossing grain to her chickens directed me to the beekeeper's house, on the far edge of the village. I spotted the man himself over the wall, gathering windfalls from beneath the apple tree. He looked up, unsurprised to see me.

“Good day, Mrs Holmes.”

“Hello, Mr Miranker.”

“I'm trying to pick up the apples before the wasps find them,” he explained. “I don't like to encourage wasps to spend time in the vicinity of the bees.”

“Quite,” I answered, remembering belatedly, and with some guilt, that Holmes had once told me something of the sort. As if to make up for my own poor husbandry of the bees left to my keeping, I bent to help him clear his apples.

“Was there something I might do for you?” he asked after a while.

“Oh, yes,” I said. I dropped my load of bruised and spoiling fruit in the barrow and fetched the frame from my bicycle. He led me to a sunlit potting bench and moved away the collection of clay pots and gravel. I dusted off the boards and laid out my frame.

“I wonder if you can tell me anything about these queen cells?”

“Apart from the fact that they are empty?”

“Can you tell if they were opened from inside, or from without?” I had brought the magnifying glass, but he did not take it.

He picked up the frame, tilting it back and forth to the sunlight, while I told him my speculations.

“The hive is all by itself on the hillside. The nearest hive is nearly a mile away. Here's what I was wondering.” And I laid out for him the story I had built in my mind.

When a hive swarms, the reigning queen takes with her the better half of the hive, leaving behind the honey, an entire hive's worth of infant workers in their cells, and one or several potential queens. The workers who remain behind nurture the queen cells until the first one hatches, at which point she tries to slaughter her potential rivals. Generally, the hive prevents her from killing all of them until she has returned successfully from her mating flight, ready to take up her long life as the centre of the hive's future.

The hours that she is away is a time of enormous vulnerability for the hive. A hungry bird, a chill wind-and their future fails to return. And if her hive has permitted her to kill all potential rivals, they are doomed.

The summer had seen periods of wet, and wind was always a problem near the sea, but I wondered if the remoteness of the hive had driven the queen to take a longer nuptial flight than normal, before the drones from her own and other hives caught her up.

I was not going to go so far as to suggest that loneliness had killed them, but that was the underlying idea.

Mr Miranker listened to this, radiating doubt as he methodically went over the frame I had brought him.

I asked him, “How do the drones know that the new queen is taking off?”

“There is, literally, a hum of anticipation that builds throughout the hive. And the queen sings, quite loudly. Then, once she is in flight they simply see her-she generally chooses a clear day on which to fly. It is also possible that she ‘speaks’ by sounds inaudible to human ears, or by her motions, or even by emitting an entire language of smells.”

“How far can a drone fly?”

“Bees can fly two or three miles.”

“What would happen if something kept her own drones from reaching her?”

Miranker glanced sideways at me, realising that he was discussing the mechanics of apian sex with a woman young enough to be his granddaughter. He cleared his throat, and replied gamely, “Generally speaking, drones from hives all around respond to the call of a virgin queen. Hundreds, even thousands of them.”

“And if there were no other hives nearby?”

“There are always other hives nearby.”

“As far as I can see, the nearest bees to that hive are those in our orchard, more than a mile away.”

Miranker stared at me. “Are you suggesting that the queen's flight went, er, unconsummated?”

“Is that possible?”

“It is more likely that she did not return at all. That is why the hive produces a number of queen cells, in anticipation of failure.”

“But if she was too bloodthirsty for them? If they didn't stop her from killing her rivals?”

“Then it might well be too late for them to raise up another from the eggs left by the previous queen.” But just as I was thinking that I had succeeded in solving Holmes' mystery, he said, “However. These cells have been opened from within.”

“What, all of them?”

“The five I see here. How many were there in all?”

“Twenty-one. They all looked pretty much-”

“Twenty-one? All like this?”

“As far as I could see.”

“I should say that all of these hatched.”

“You mean, this hive has made twenty-one queens? Every one of them hatched, and fighting for primacy?” Absolute chaos, if that was the case.

“More likely, hatched and flying off into the blue. In some hives, the difference between a cell intended for swarming and one intended for supersedure-replacing the queen-is clear. Here, I would not be so certain.”