He looked at Joe with guarded friendship. ‘Glad you’re here,’ he said. ‘Too many mysteries! Having this in common, each with other – no mystery at all! Distressing, even horrifying, but all susceptible to explanation and the only mystery is that they should have happened in the same month. I expect you’re a clever man – wouldn’t be here if you weren’t – but I think you’re on a loser considered purely…’ He hesitated for a moment and continued, ‘considered purely as a matter of forensic detection. I’ll give you my explanation if you like which is “This is India ”. India is not Seven Dials. Still less are we investigating a country house mystery – roast beef for lunch on Sunday, vicar coming round for a glass of sherry after matins, body on the library carpet and a domestic search for the truth through a cast of predictable characters. This is India, I say again, where the strangest things happen. I’ve lived for years on the north-west frontier where any Pathan would merely acknowledge the presence of a malignant spirit. They exist, you know.’

‘A Churel, perhaps,’ said Joe, remembering the word with difficulty.

‘A Churel, certainly,’ said Prentice, surprised. ‘And I could think of half a dozen phenomena the existence of which is widely believed to put beside your Churel. This is the country of Kali, the Destroyer, as well as of Vishnu, the Benevolent.’ He paused and Joe sensed that, though there was much more Prentice had to say, was even keen to say, he was about to obey the code of the Club which forbade that anyone should talk shop and was preparing to close down the conversation.

‘Keep it light, don’t dance with the same girl more than three times and don’t monopolise anyone’s time. Be like a butterfly and pass from flower to flower, that’s the drill for a Club Dance,’ Joe silently reminded himself. At that moment, the dance band of the Shropshire Light Infantry went into a foxtrot. He smiled, nodded and got to his feet, going through the ritual distancing gestures. Then, ‘Oh, one thing before dance floor duty calls, sir… Hardly like to ask but two minutes now will save us an interview at a later stage which would probably waste time for both of us…’

‘Carry on, Sandilands,’ said Prentice equably. ‘These are unusual circumstances and, if I understand the women’s concerns correctly, time is of the essence.’

‘Then I won’t apologise for asking you to go back to 1913, to the death of Alicia Simms-Warburton. The report mentions a piece of information which triggered her dash to the river and thence to her death…’

‘You mean the butterfly. The Camberwell Beauty.’ Prentice sighed. ‘I’ve always held myself in some way responsible for Alicia’s death. Indirectly, of course, but I am aware that if I hadn’t passed on the information she would never have been crossing the river that day. Though when the significance of the butterfly strikes you, you might begin to agree with me that I was used. Fate’s instrument. No more than that.’

‘The significance of the butterfly?’

‘Yes, the Camberwell Beauty. That’s quite odd. They’re very rare in India but almost unknown in England. No wonder she was excited! Don’t suppose you’ve ever seen one? It’s large with black, drooping wings. Sinister-looking object, if you ask me. The local Indians call it something like Harbinger of Kali – in other words, precursor of death.’

He paused for a moment, assessing Joe’s response.

‘And the man who brought you the information? Was he known to you?’

‘I’d better explain. Everybody knew about Alicia’s passion for collecting. It was quite a joke, you might say, but everyone, English and Indian, indulged her. Brought her specimens, told her where they’d spotted something interesting, that sort of thing. I’m afraid she used to tip the Indians far too heavily. Simms-Warburton had to speak to her about it – she was spending half the housekeeping on creepy-crawlies, he used to complain. Well, one day an Indian came asking to speak to me. I took him for one of the gardeners (though I was to find later he was no such thing – chap just disappeared). He had no English and only spoke his village dialect. He came to me because he knew no one else would be able to make any sense of what he had to say. Could hardly make it out myself. And what he had to communicate was a request that I should tell the lady who collects butterflies that there had been a hatch of a very rare one in the willow trees along the river by the ferry on the far bank. I thought he was just another chap trying to get money out of Alicia and was on the point of sending him away. Then he launched into a vivid description of the creature and told me its name, Harbinger of Kali, and, I must say, I began to be intrigued. Looked the thing up in a book and checked he knew what he was talking about of course. I gave him a tip – a reasonable amount, he’d have done better with Alicia – and passed the information on. Straight away. Butterflies wait for no man or even memsahib. Never set eyes on the fellow again.’

‘Another tool of Fate?’ murmured Joe.

‘Very probably. We must continue this conversation another time. I think there is much more you want to know. Now, are you dancing, Sandilands? I’m sure Nancy would let you pilot her round the floor.’ And, with a bow to the returning Nancy, he turned and walked away.

‘Well,’ said Nancy, ‘what did you make of that?’

‘Formidable man,’ said Joe, reflectively. ‘I’ve met one or two but I think he tops my list. What can I guess? Faithful friend, implacable enemy, devious schemer – am I getting it right? I think he’d usually get his way’

‘That’s not bad,’ said Nancy. ‘Not bad at all. That’s very much Giles as I understand him. The only thing you leave out is that his men are devoted to him. Some touching and remarkable stories came back from France. Servants too. They’re very loyal and you never hear gossip spreading from the Prentice bungalow. The bearer who was killed in the fire they say never left Giles’ side so the fire was a double disaster for him, poor chap.’

‘Lucky not to have lost his daughter. She was smuggled out by her ayah, I understand.’

‘Yes. And she’s back in India, they tell me. She must be eighteen now. She’s been away at school in Switzerland and sailed into Bombay last week under the sketchy chaperonage of Millie Bracegirdle! She’s spending a few days to recover from the voyage with an aunt and then coming on back to her father here at the station. Giles doesn’t show many emotions but he loves his daughter and if he were capable of showing excitement, I’d say he was excited at the thought of her coming back into his life again. He’s got plans for a party to welcome her back to the regiment so perhaps he isn’t such an icicle after all. Now, come and dance with me! Let’s give the gossips something to gossip about!’

The band went into a slow waltz and Joe gathered her to him. ‘The Destiny Waltz’. His mind went back at once to France. This had been one of the few gramophone records they owned and he had last heard the tune being played on a wheezy accordion in an estaminet not many miles behind the lines. And here it was again. ‘Police boots!’ thought Joe and, with a quick glance down at Nancy ’s silk stockings and delicate, high-heeled kid shoes, he said, ‘Can you do a reverse turn?’

‘I don’t know,’ said Nancy. ‘I don’t think I’ve ever tried.’

‘Come on, then,’ said Joe, with a quick glance around which told him that, satisfactorily, every eye in the room was following them. ‘Hold tight! Now!’

‘That was good!’ said Nancy. ‘Let’s do it again!’

Under the proximity engendered by this complicated manoeuvre, Joe let his cheek brush hers.

‘What shall we do next?’ said Nancy.

Joe raised an eyebrow.

‘No! I wasn’t talking about a hot, squashy time behind the potted palms in the kala juggah! What over-heated stories have you been listening to about memsahibs? I was talking about the investigation, for goodness sake! Just remember I’m the Collector’s lady! The Governor’s niece! Caesar’s wife!’