The icy wind whipped around my skirts as I half-leapt, half-fell out of the door at the lower level. The man in the grey cloak was already half-way down the first flight of iron stairs and was rapidly disappearing into the blizzard. I had no time to lose. I set off in pursuit, my booted feet slipping and sliding on the frozen steps.

Away from the shelter of the observatory's walls, formed of blocks of stone transported with vast labour from the quarry many thousands of feet below, the force of the snow-storm blasted stinging particles of ice into my face and eyes, half-blinding me. My gloves, a pair made in finest leather by Chester Jefferies of London and intended for use in the tropical lowlands, were barely up to the job of preventing my hands from sticking to the ice-cold stanchions and banisters. Gripping as tightly as I dared, I hurried down the steps, occasionally bracing myself as a more powerful gust threatened to toss me against the rocks or throw me over the side of the safety rail.

I could expect no assistance here. The blizzard meant that no craft of air or land could make safe progress, and the man in grey had already disabled two of my most experienced colleagues. It was all down to me now.

*

The first inkling of the import of the mission I had found myself embarked upon was in a scientific laboratory, part of a private estate set in a quiet suburb of Mombasa. It was the kind of elaborate establishment which a certain class of Englishmen often chose to build in the more foreign parts of the Empire: grounds enclosed by a high wall surrounding a sprawling residence, itself set around a central courtyard in the Italianate style.

In this case, the buildings were even more extensive than convention would dictate: as well as kitchens and storerooms and servants' quarters, there were several buildings not quite so easy to immediately account for. My training in observation and deduction, courtesy of Her Britannic Majesty’s Government - not to mention several years of field experience - would have led me to infer the existence of a machine hall, even if the obvious engine house, with its tall chimney belching smoke, and the humming and chattering of gears and ratchets had made such a deduction inevitable.

I had been invited to call upon the gentleman known to me as Doctor Quentin Porter on the pretext of soliciting a charitable donation from a man of obvious means and a relatively recent arrival here in Mombasa. The contribution was to be directed to the foundation which I ran - quite genuinely, even it was also a cover for some of my more sensitive roles - to improve the cultural, educational and social standing of local residents - all residents, I should stress, even those not originally from the islands of Great Britain. I judged that Doctor Porter would have been in Imperial East Africa long enough to have learned that a suitable sum would provide a reliable entry into the more exclusive sections of polite society, although of course any suggestion that this was a fee or, worse, a bribe would be refuted in the strongest possible terms.

My steam car was admitted through the front gates with alacrity, the gatekeeper clearly apprised of both the importance and the schedule of my arrival. Even before the car had crunched to a halt on the raked gravel drive, the double doors had been flung open and a small battalion of staff had emerged, clearly under the command of the Major-domo in white tie and tails. His staff hurried to open the car door, having first deployed a low step for my convenience. As I emerged, a man with an obviously European skin tone appeared at the doorway, dressed in the lightweight tweeds which engine-powered looms have made possible and the local climate has made desirable.

My host greeted me formally, then guided me into the house; from the entrance hall, he politely directed me through a doubled set of heavy doors both lined with green baize into what was undoubtedly a very fine library, many of the books displaying the patina of extensive use. Outside, there was the blinding light and equatorial heat of an African afternoon which had required the strategic deployment of my parasol and fan to deflect even just for the few steps between steamer and portico; within, with the shutters closed, it was cool and dark, cooler even than I might have expected.

"My dear Miss Robinson," Doctor Porter said, closing the doors behind us firmly, shutting out both the noise of the calculating machinery and the cohort of servants, "Thank you for accepting my invitation."

"It is, of course, my pleasure," I replied. Porter nodded thoughtfully, then directed me to one of several comfortable chairs which littered the room; it seemed to me that he had something on his mind.

"Let me say at once," he continued after a few moments, "That I am entirely willing to contribute a considerable sum to your foundation, to support the many Good Works that you undertake therein."

"That is very generous of you," I said graciously, "I am sure the many people supported by the foundation will be forever grateful."

He nodded again. "But there is another matter, one of much greater import, I believe, which I would wish to discuss with you."

"With I?" I answered, contriving to sound a little confused, although his mannerisms led me to believe that he was being entirely earnest.

"Yes, Madam, with you," he insisted, "I have heard it suggested that you have the ear of one or two highly influential people, people beyond those I could talk to directly. People who might know how best to respond to the suspicions I have formed."

I sat back. "Well, I do have a few acquaintances with a certain amount of influence," I said modestly, "But first you tell me what on earth has caused your concerns."

"Of course." He sat heavily in another of the chairs, pulled a handkerchief from his breast pocket and ran it over his face. "I am a geologist and vulcanologist," he began, gesturing at some framed certificates displayed pride of place on one wall, "I am employed by the Royal Society in London to survey volcanic features in all parts of Imperial East Africa and report on their stability."

That made much sense to me. The Royal Society had been the focus of the Empire's scientific and technical advances for many decades and certainly went out of its way to commission reports on abstruse and recondite subjects which might just prove to be important one day.

"Their patronage has allowed me to acquire a set of powerful calculating engines," he went on, "Enabling me to model various geological features and assess their soundness."

I nodded sagely but said nothing.

"You know the impressive mountain called Kilimanjaro?" the Doctor went on.

"Of course," I replied promptly. I had travelled extensively in many parts of this vast continent. "An imposing snow-capped peak in the region known as Tanganyika and clearly visible from the vast plains which form the Serengeti."

"Precisely so," he confirmed, "The conical shape of the mountain shows clear signs that it was formed over millions of years by volcanic outflows, and has long been considered extinct. But my simulations using the calculating engines suggest that Kibo summit, the highest and most recent peak on the mountain is merely dormant, rather than extinct."

"So it could become active again?"

"Perhaps. It was last active many tens of thousands of years ago, but it could still erupt tomorrow, throwing millions of tons of smoke and pulverised rock into the atmosphere."

"Tomorrow?" I was startled by the assertion.

"Well, probably not," he answered soothingly, "Although the impact of such an eruption would be calamitous, for the natives and the wildlife and, most importantly, for the business of the Empire."

"The Empire?" I demanded, now more alarmed, "How so?"

"Travel by airship would be impossible for hundreds, thousands of miles around," the Doctor said seriously, "It would have incalculable effects on trade and security."

I shivered in the coolness. It was the first time I had felt cold since I left London all those years ago, boarding the Iphigenia, the airship which had taken me on the first leg of my journey to British East Africa.

"Well, that would indeed be calamitous," I replied, recovering my composure, "But is the mountain really likely to explode?"

"In the ordinary scheme of things, dear lady, absolutely not," he assured me, "But I need to tell you about two pieces of information which have fallen into my lap, entirely by chance."

I frowned, which might not have been the most ladylike of responses. "Please proceed."

"Firstly, I received the proceedings of a scientific conference tangentially aligned with my own scientific interests. Skimming through it, I noted that there was a paper presented on the astronomical observatory currently being built on the mountain-top, on Kibo summit itself. Most unusually, the observatory is privately funded, with no investment or oversight from the Royal Society, although exactly where the money is coming from was not stated."

My frown deepened. "Surely that must be a good thing," I replied, "Scientific research without financial contributions from Her Majesty's government?"

Doctor Porter smiled wanly. "True enough," he replied, "If it was not for the letters I have been receiving." He picked up several pieces of paper from a nearby table and handed them to me.

"The Professor who is, most unusually, in sole charge of the Kibo Observatory, one Anthony Scott, is apparently an astronomer from an obscure university in the north-east of England," he went on, "And this letter from a distant cousin who, by chance, attends the same university, tells me that Professor Scott has, as far as can be seen in the scientific literature, no background in astronomy and has a surprisingly poor command of English. Investigating further at my request, my cousin tells me that a man with a very similar name and appearance, one Anton Schrötter, was a chemist with a background in explosives at the Technical University of Vienna."

I leaned forward, greatly interested in what Doctor Porter had to say. "Go on."

"All this leads me to suspect that this Professor Scott is actually some kind of agent for the Austro-Hungarian Empire, and that the observatory is a cover for a plot to dig deep into the mountain and set off a vast explosion which could wake up the dormant volcano!"

Introduction Part 2