While I held the lantern above him and directed its beam wherever required, Mr Holmes crouched to subject this strange structure to an examination with his magnifying lens. Five minutes sufficed to satisfy him, for he rose to his feet and put away his lens. Then, placing his hands firmly against the side of the thick stone disc, he proceeded to exert his full strength, in a somewhat oblique direction, against the weighty object. I did not notice anything, but some slight change must have occurred for Mr Holmes stopped and grunted in satisfaction.

'It moves,' he said, a note of triumph in his voice.

'What does it mean?' I asked.

'It means our little mystery, the riddle of the cryptic verse, is nearly solved.'

'I do not understand, Mr Holmes.'

'You will remember we agreed that the verse was a set of instructions, probably for the disinterment of something concealed – something precious. Since the symbolism of the mandala structure is used in the verse, what is more logical than to conclude that the instructions refer to an actual mandala – but one that is palpably whole and upright.'

'So that we can move around it in particular circles, like the instructions say?' said I puzzled. 'But…'

'No no, my dear Hurree. Not to move around it but to move it. My cursory examination has revealed that this structure has not been hewn from the a single piece of stone but has rather been assembled – each layer of it – from separately sculpted pieces, each capable of being moved, or rather rotated, around a central axis.'

'Like the tumblers of a lock?'

'Exactly. Your choice of an analogy is a happy one, for this mandala is – if my reasoning is correct – a lock, albeit an unusual and considerable one.'

'But what about a key then, Mr Holmes. We do not have it.'

'Oh, tut, man. We need not be so literal. The verse is our key.'

'I have been very obtuse…' said I, abashed, but Mr Holmes had no time for my self-reproaches, and was in a fever to begin testing his theory.

'Now, Hurree, if you could lend a hand here, and… excuse me, Reverend Sir,' he turned to the Lama Yonten, 'if you could kindly read the verse to us.'

The Grand Lama had now recovered and insisted on holding the lantern, while the Lama Yonten unrolled the mandala scroll and read the lines on the back. 'Ora Svasti. Reverence to thee…'

'We can skip the benedictory lines,' interrupted Holmes 'and proceed with the actual instructions.'

'As you wish, Mr Holmes,' replied the Lama, quickly perusing the verses, underlining the word with this bony forefinger. 'Let me see. Hmm… ah yes… the instructions start here. "Facing the sacred direction…"'

'What would that be?'

'North, Mr Holmes. Shambala is properly referred to as "Shambala of the North."'

'So that would necessitate us having our backs to the entrance and facing the mandala from that direction. Let us see now…'

'I have it, Mr Holmes,' I cried exultantly, scraping away the snow at the base of the mandala exactly across the entrance.'There is a crossed vajra [38] inscribed on the floor here. This probably marks the direction from which we start.'

'That is the very place where the Grand Lama must sit when meditating on the mandala! said the Lama Yonten.

'So we can take it as our starting point,' said Holmes briskly. 'Now let us have the next line in the verse.'

'"… turning always in the path of the Dharma wheel…" '

'Bear in mind, Hurree, that all our operations will have to be conducted clockwise. Pray continue, Sir.'

' "… Circle Thrice the Mountain of Fire."'

'That would be the base of the mandala. See the design of flames carved into the stone. Now, Hurree, let us attend to it with a will.'

It was not an easy task. Both Mr Holmes and I were grunting with the effort, but finally the giant disc moved slowly. As per the instructions we rotated that bally deadweight three times around its axis, finishing exactly where we started, by the crossed vajra mark on the floor. I collapsed with exhaustion.

'"… Twice the Adamantine Walls…" ' the Lama droned on.

'Come on Hurree,' Mr Holmes exhorted me. 'This one will be easier. It's much smaller.'

Mr Holmes was right. The 'Adamantine wall' disc wasn't as heavy as the ' Mountain of Fire ' disc, and we only had to rotate it twice. The 'Eight Cemeteries' disc was even easier, while the one after that, 'The Sacred Lotus Fence' disc, I managed by myself.

On the fifth tier the mandala changed shape; from the circular discs of the earlier mountains, walls and fences, to a square plinth with protuberances on each side – the four walls of the Sacred City and its four gates.

' "… Then from the Southern Gate turn to the East…"'

Following the instructions we turned the square plinth a three quarter turn. Now came the last item in the verse. 'The Innermost Palace ', which was the pagoda with the canopied roof, on the very top of the mandala. It was a tremendously exciting moment. While Mr Holmes gave the little pagoda half a turn from the South to the North – as the instructions specified, we waited with bated breath for the result.

Nothing happened.

A cold chill of disappointment coursed through my body. It seemed to me that somehow Mr Holmes must have made a radical mistake in his chain of reasoning.

'We are undone, Hurree,' said he, a pained look on his face. He turned away, and biting hard on the stem of his pipe paced restlessly about the chamber, kicking up a small storm of powder snow in his wake. He kept up his choleric perambulations for about ten minutes, when all of a sudden a happy thought seemed to strike him. He brightened at once, and snapped his fingers.

'The Vajra throne,' he cried. 'We have omitted "… and sit victorious on the Vajra throne…"'

'But that only seems to be a concluding symbolism of some kind, Mr Holmes,' said the Lama Yonten.

'We have moved everything movable in the mandala! said I despondently. 'There is nothing more left to manipulate.'

'Let us see,' said Holmes, going over to the mandala. He careftilly studied the pagoda on the top with his lens, and then with the thin blade of his pocketknife, gently prised open the miniature doors of the littie temple. Within the pagoda was a tiny crystal throne carved in the shape of a crossed vajra. It was a beautiful thing. As the Grand Lama directed the beam of the lantern on it, Mr Holmes carefully studied this miniature objet d'art closely with his lens.

'But what shall we do now, Mr Holmes?' said I. 'We have no instructions about what to do with it.'

'Ah, but we do, Hurree,' said he cheerfully. He paused. 'We sit on it.'

With that he put the tip of his forefinger on the crystal throne and gently pressed it down. There was an audible click – as if some kind of lever had been activated. Then the crystal throne began to glow with an eerie green light. It slowly became brighter till its radiance suffused the North wall of the chamber with a light as brilliant as that of a full moon in mid-summer. The mandala itself began to vibrate spasmodically, the tremors increasing in intensity till the entire temple shook in an alarming manner.

To our consternation some of the icicles broke off the roof of the chamber and crashed onto the floor, throwing up sprays of snow. Mr Holmes quickly grabbed the Grand Lama and, doing his best to cover the lad's body with his own, retreated to a corner of the chamber. The Lama Yonten and I also hurriedly backed away from the mandala, which seemed to be the source of all this tremendous energy.

As I retreated to the rear wall, I tripped on a piece of fallen icicle and staggered backwards. I expected to fall against the wall and put my hands behind me to take my weight, but to my surprise I encountered nothing and fell clean backwards. Even more alarming was the fact that my descent backwards did not stop at the floor but continued in a precipitate and confusing manner for quite some time, till finally I landed with a painful bump, somewhere in utter darkness.