‘I’ve known men with neurasthenia,’ said Joe carefully, ‘and mostly, they’ve known the difference between that state and normality. I’m guessing you do too.? He gave Simpson a level gaze. ‘I’m guessing that you’re telling us what were your actual impressions as you lay injured.’

Simpson nodded. ‘Yes, I’m sure in my own mind of what I saw but is my own mind a reliable place from which to be viewing the world?’

‘Let’s assume for the moment that it is,’ said Joe. ‘And let’s further assume that you were not visited by an apparition. We’re left with the fact that you were approached by a woman wearing Madame de Neuville’s shoes, stockings and skirt and, therefore, reasonably, as you saw no further, we must assume that you did indeed see Isabelle de Neuville and that she survived the crash.’

‘But only one woman survived and that was Alice Conyers,’ objected Carter.

A terrible theory was beginning to form in Joe’s mind. Something Marie-Jeanne Pitiot had innocently said reinforced his theory but it was so fantastical and outrageous he tried to push it away. It came back with greater force. Reluctantly he spoke again.

‘There is a way to explain all this,’ he said. ‘But only one way. And, though I think it’s ludicrous, I’ll outline my idea anyway. Now – one woman only survived the crash. This is a fact. But which woman? If Simpson can believe the evidence of his one eye, it was the Frenchwoman. Imagine the scene. Miles from anywhere, no hope of rescue for hours. All dead but Simpson who, to all appearances, was dead or as good as. Just Isabelle de Neuville alive.’

Joe took a deep breath and plunged on. ‘Suppose she found the body of Alice Conyers, broken-backed, dead. Alice with her hopes of a new life in a new continent, a huge fortune, a marriage ahead of her. Suppose Isabelle is dissatisfied with her own life – this is conjecture now – suppose she is fleeing Paris, running away from an irate or boring husband, from debts, from loneliness – might she not be tempted to change places with Alice? There were no witnesses. She crept around – stealthily was your word for it, Simpson – checking that the other passengers were dead. If she realized Simpson was alive she thought he was blind anyway so that was no obstacle. She takes Alice’s clothes off her body, the top layer only, and she substitutes her own. If they didn’t fit very well – no problem – they would be so torn and bloodstained no one would notice.’

Simpson nodded silently and Carter made no comment so Joe went on. ‘But someone did notice something slightly off key about the clothes! Marie-Jeanne Pitiot was made Alice’s personal nurse and she it was who had the task of stripping the damaged garments off her. She remembers being surprised to discover that under the grey serge were underpinnings of emerald green silk, if I remember it correctly. It’s her theory that Alice had bought these frivolities in Paris and was wearing them as a hidden sign of revolt against her austere upbringing and I find this totally credible but, on the other hand, there is a more sinister and equally convincing reason. It would have been almost impossible for a woman injured as Isabelle undoubtedly was herself in the accident to wrestle the undergarments from a lifeless corpse and put them on herself and repeat the procedure with her own clothes. Not a task for the faint-hearted nor one for someone suffering from shock, cracked ribs and a facial wound.’

‘Just about possible for her to exchange the outer garments, I would have thought,’ said Carter, ‘and that would have taken incredible determination.’

‘Not so sure,’ said Simpson. And, turning to Joe, ‘I think you must have been in the war. A survivor. You know what battlefields are like. This was very like a battlefield…’

‘And people find surprising strengths despite their injuries. If their resolve is strong they can move mountains,’ said Joe. ‘Yes, I’ve witnessed that many times.’

‘So,’ said Simpson, taking up the theory, ‘having taken her clothes and her bag — ’

‘Her bag?’ said Carter and Joe together.

‘Oh, yes, that would have been a vital part of her scheme! Alice was carrying a bag with her personal documents in it. And more than just her passport and tickets and so on – it contained her diary. She showed us all. It was one of those leather jobs with a lock and key that are so popular with girls. A five-year diary. She’d kept it up to date, she said, until she got to Paris and then life became so exciting she didn’t have the time to fill it in. Well, that would have given Isabelle de Neuville plenty of background to base her character on, wouldn’t it? And then there was the leather folder!’ he added, memory returning with a rush. ‘It contained all the information she needed to prepare herself for taking over the family business when she got to Bombay. She took us on a quick canter through that too! A day’s work learning up the facts in it and anyone could make a reasonable showing as the heir apparent to the family fortune! So, what have we got? She’s stolen the other girl’s clothes, her documents and her identity!’

‘Oh, come on, now! People would be able to see it wasn’t Alice!’ objected Carter. ‘They’d take one look and know it was someone else, wouldn’t they, Simpson? You said they were a bit alike but it was the differences you stressed.’

‘That’s true. Because it was the differences that were so immediately striking. You know – the one so sophisticated, the other so naive. But underneath the outer layers, well yes, there were similarities. Hair colour – light brown. Eyes – blue. With a change of clothes Isabelle could have been Alice’s older sister. There could have been only a year or two’s difference in age. Alice was very childlike for her age. She was twenty-one but you’d have guessed sixteen.’

‘With a change of clothes could Isabelle have become Alice? That’s the question we have to explore.’

Simpson weighed his impressions with care, finally concluding, ‘Yes, I think she could – given a certain acting ability – she could have got away with it. I’ll tell you why… I told you Alice chattered on and on. We knew all there was to know about Miss Conyers by the end of lunch! She had no close relations left alive and the people she was to meet in Bombay, she had never met before. Good God!’ he exclaimed, warming to the idea. ‘Yes, she could have pulled it off!’

‘A terrible risk to take,’ said Carter. ‘Think about it!’

‘I’m not so sure,’ said Joe. ‘She was plunging into a completely new life where no one knew her. If there were any lapses of memory or bits of strange behaviour she could blame it on the rail crash injury. She’d need a lot of confidence, of course.’

‘Oh, she had that all right!’ said Simpson. ‘I’d say she had a very cool head. Highly intelligent woman, was my judgement of her. But to steal someone’s life and fortune like that! I can’t really believe it! I liked her! I can’t think she would have done such a thing.’

‘Before you both get carried away,’ said Carter, ‘there’s an obstacle you simply can’t get around! Isabelle de Neuville couldn’t possibly play the part of Alice Conyers because she was French, wasn’t she? Pretty damn obvious! Can’t think why you haven’t raised it!’

Joe looked a question at Simpson.

‘Her English was faultless,’ he said. ‘Only a slight accent. A bit too pure, if you know what I mean. You know how foreigners seem to speak better English than we do because they don’t salt their speech with the latest slang as a native speaker does?’

‘Can you be sure that she was French?’

‘Oh, yes,’ said Simpson smiling. ‘I heard her screaming at her maid before the train started. You’d have to be French to have a vocabulary like that! Her clothes, her luggage, her mannerisms – all French.’

‘Well, that’s it then,’ said Joe. ‘That explodes our theory!’

‘Your theory, old man!’ said Carter. ‘Still, very inventive! I enjoyed our little excursion into the realms of fantasy!’