“They are swarming,” Holmes said.

I looked up from the newsprint to stare first at him, then at the thick document in his hand.

“Who- Ah,” I said, struck by enlightenment, or at least, memory. “The bees.”

He cocked an eyebrow at me. “You asked what it meant, that the hive had gone mad. It is swarming. The one beside the burial mound in the far field,” he added.

“That letter is from your beekeeper friend,” I suggested.

By way of response, he handed me the letter.

The cramped writing and the motion of the train combined with the arcane terminology to render the pages somewhat less illuminating than the personal adverts in the paper. Over the years I had become tolerably familiar with the language of keeping bees, and had even from time to time lent an extra pair of arms to some procedure or other, but this writer's interests, and expertise, were far beyond mine. And my nose was too stuffy to detect any odour of honey rising from the pages.

When I had reached its end, I asked, “How does swarming qualify as madness?”

“You read his letter,” he said.

“I read the words.”

“What did you not-”

“Holmes, just tell me.”

“The hive is casting swarms, repeatedly. Under normal circumstances, a hive's swarming indicates prosperity, a sign that it can well afford to lose half its population, but in this case, the hive is hemorrhaging bees. He has cleared the nearby ground, checked for parasites and pests, added a super, even shifted the hive a short distance. The part where he talks about ‘tinnitusque cie et Matris quate cymbala, circum’? He wanted to warn me that he's hung a couple of bells nearby, that being what Virgil recommends to induce swarms back into a hive.”

“Desperate measures.”

“He does sound a touch embarrassed. And I cannot picture him standing over the hive ‘clashing Our Lady's cymbals,’ which is Virgil's next prescription.”

“You've had swarms before.” When bees swarm-following a restless queen to freedom-it depletes the population of workers. As Holmes had said, this was no problem early in the season, since they left behind their honey and the next generation of pupae. However, I could see that doing so time and again would be another matter.

“The last swarm went due north, and ended up attempting to take over an active hive in the vicar's garden.”

That, I had to agree, was peculiar: Outright theft was pathological behaviour among bees.

“The combination is extraordinary. Perhaps the colony has some sort of parasite, driving them to madness?” he mused.

“What can you do?” I asked, although I still thought it odd that he should find the behaviour of his insects more engrossing than dead Druids or the evil acts of spoilt young men. Even the drugs problem should have caught his attention-that seemed to have increased since the previous summer, I reflected: How long before Holmes was pulled into that problem once again?

“I may have to kill them,” he declared, folding away the letter.

“Holmes, that seems a trifle extreme,” I protested, and only when he gave me a curious look did I recall that we were talking about bees, not Young Things or religious crackpots.

“You could be right,” he said, and went back to his reading.

I returned to The Times, my eye caught again by the farmer's letter demanding that a guard be mounted on Stonehenge at next year's solstice, so as to avoid either riots or the threat of a dramatic suicide. I shook my head and turned the page: When it came to communal behaviour, there were many kinds of madness.

* The events of those months may be found in The Game, Locked Rooms, and The Art of Detection.

WE HAD LEFT OUR HOME ON THE SUSSEX COASTLAND one freezing, snow-clotted morning back in January, to return on a high summer afternoon when the green-gold countryside was as full and fragrant as a ripe peach in the palm of one's hand.

I was pleased that we had caught the Seaford train rather than the one to Eastbourne. This meant that, instead of motoring through an endless terrain of seaside villas and sunburnt holiday-makers, we quickly shook off the town to cross the meandering tidal reaches of the Cuckmere, then threw ourselves at the steep hill onto the Downs.

Sussex had always enchanted me, the mix of sea and pasture, open downland giving way to dark forest, the placid face of beach resorts cheek by jowl with the blood-drenched site of the Norman conquest. Daily, one encountered history protruding into modern life like boulders from the soil: Any foundation dug here was apt to encounter a Bronze Age tool or a Neolithic skeleton; ancient monuments dotted the hillsides, requiring ploughs and road-builders to move around them; place-names and phrases in the local dialect bore Medieval, Norse, Roman, Saxon roots. In this land, in the hearts of its people, the past was the present: It did not take much imagination to envision a local shepherd in winter-bearded and cloaked beneath his wide hat, leaning on a crook-as Woden, the one-eyed Norse god who disguised himself as a wanderer.

The motor that had coughed and struggled its way up the hill now seemed to sigh as it entered the tree-lined downgrade towards East Dean. Holmes shifted and reached for his cigarette case, and the abrupt motion, coming when it did, suddenly brought the answer to Holmes' mood as clearly as if he had spoken aloud: He felt Sussex closing in over his head.

Sussex was his chosen retreat from the press of London, the rural home in which he could write and conduct experiments and meditate on his bees yet still venture out for the occasional investigation; now, after seven busy months in free flight across the globe, it had become small, dull, tedious, and claustrophobic.

Sussex was now a trap.

I had forgot for the moment that Mrs Hudson would not be there to greet us, but when Patrick pulled into the freshly gravelled circle in front of the house and shut off the engine, the front door remained closed.

Holmes climbed down from the car before its noise had died. He tossed his coat across the sun-dial and dropped his hat on top, then set off in shirt-sleeves and city shoes, heading in the direction of the far field near the burial mound.

Patrick was well used to my husband's eccentricities, and merely asked me if I wanted the trunks upstairs.

“Thank you,” I told him.

The front door opened then, to reveal Mrs Hudson's helper Lulu, pink and bustling and spilling over with words.

“Ma'am, how good it is to see you, to be sure, Mrs Hudson will be so vexed that she couldn't be here, and I hope you don't mind, but yesterday night a gentleman-”

The sudden appearance of a person who was not the one I wished to see, and a sudden unwillingness to immerse myself in the busy turmoil of homecoming, had me adding my own coat and gloves to the impromptu hat-stand and following in Holmes' wake, out onto the rolling expanse of the South Downs.

Once clear of the flint wall around the gardens, I could see him ahead of me, striding fast. I did not hurry. It mattered not in the least if I caught up with him before he turned back for home, which he would do soon-even a hive infected with madness was bound to shut down with dusk. I merely walked, breathing in the air of the place that, for nine years, had been my home.

My headache faded, and before long my sinuses relaxed enough that I could smell the sea, half a mile away, mingling with rich traces of hay recently cut. I heard the raucous complaint of a gull, then the lowing of a cow-no doubt Daisy, belonging to the next farmer but one, prized because she bore a healthy calf every year like clockwork and gave the creamiest milk that a bowl of porridge had ever known. The rattle of a motor-cycle followed the roadway between Eastbourne and Seaford; five minutes later, the evening train from London whistled as it drew near Eastbourne.