‘You mean that he was an outsider, that he came from the mainland?’

‘Yes. He probably hid in that cave until he got his chance.’

Poirot shook his head. He said:

‘Would she go there to meet such a man as you describe? No, she would laugh and not go.’

Rosamund said:

‘She mayn’t have known she was going to meet him. He may have sent her a message in some other person’s name.’

Poirot murmured:

‘That is possible.’

Then he said:

‘But you forget one thing, Mademoiselle. A man bent on murder could not risk coming in broad daylight across the causeway and past the hotel. Someone might have seen him.’

‘They might have-but I don’t think that it’s certain. I think it’s quite possible that he could have come without anyone noticing him at all.’

‘It would bepossible, yes, that I grant you. But the point is that he could notcount on that possibility.’

Rosamund said:

‘Aren’t you forgetting something? The weather.’

‘The weather?’

‘Yes. The day of the murder was a glorious day, but the day before, remember, there was rain and thick mist. Anyone could come on to the island then without being seen. He had only to go down to the beach and spend the night in the cave. That mist, M. Poirot, is important.’

Poirot looked at her thoughtfully for a minute or two. He said:

‘You know, there is a good deal in what you have just said.’

Rosamund flushed. She said:

‘That’s my theory, for what it is worth. Now tell me yours.’

‘Ah,’ said Hercule Poirot. He stared down at the sea.

‘Eh bien, Mademoiselle. I am a very simple person. I always incline to the belief that the most likely person committed the crime. At the very beginning it seemed to me that one person was very clearly indicated.’

Rosamund’s voice hardened a little. She said:

‘Go on.’

Hercule Poirot went on.

‘But you see, there is what you call a snag in the way! It seems that it wasimpossible for that person to have committed the crime.’

He heard the quick expulsion of her breath. She said rather breathlessly:

‘Well?’

Hercule Poirot shrugged his shoulders.

‘Well, what do we do about it? That is my problem.’ He paused and then went on. ‘May I ask you a question?’

‘Certainly.’

She faced him, alert and vigilant. But the question that came was an unexpected one.

‘When you came in to change for tennis that morning, did you have a bath?’

Rosamund stared at him.

‘A bath? What do you mean?’

‘That is what I mean. A bath! The receptacle of porcelain, one turns the taps and fills it, one gets in, one gets out and ghoosh-ghoosh-ghoosh, the water goes down the waste-pipe!’

‘M. Poirot, are you quite mad?’ 

‘No, I am extremely sane.’

‘Well, anyway, Ididn’t take a bath.’

‘Ha!’ said Poirot. ‘So nobody took a bath. That is extremely interesting.’

‘But why should anyone take a bath?’

Hercule Poirot said: ‘Why, indeed?’

Rosamund said with some exasperation:

‘I suppose this is the Sherlock Holmes touch!’

Hercule Poirot smiled.

Then he sniffed the air delicately.

‘Will you permit me to be impertinent, Mademoiselle?’

‘I’m sure you couldn’t be impertinent, M. Poirot.’

‘That is very kind of you. Then may I venture to say that the scent you use is delicious-it has anuance -a delicate elusive charm.’ He waved his hands, and then added in a practical voice, ‘Gabrielle, No 8, I think?’

‘How clever you are. Yes, I always use it.’

‘So did the late Mrs Marshall. It is chic, eh? And very expensive?’

Rosamund shrugged her shoulders with a faint smile.

Poirot said:

‘You sat here where we are now, Mademoiselle, on the morning of the crime. You were seen here, or at least your sunshade was seen by Miss Brewster and Mr Redfern as they passed on the sea. During the morning, Mademoiselle, are you sure you did not happen to go down to Pixy Cove and enter the cave there-the famous Pixy’s Cave?’

Rosamund turned her head and stared at him.

She said in a quiet level voice:

‘Are you asking me if I killed Arlena Marshall?’

‘No, I am asking you if you went into the Pixy’s Cave?’

‘I don’t even know where it is. Why should I go into it? For what reason?’

‘On the day of the crime, Mademoiselle, somebody had been in that cave who used Gabrielle No 8.’

Rosamund said sharply:

‘You’ve just said yourself, M. Poirot, that Arlena Marshall used Gabrielle No 8. She was on the beach there that day. Presumably she went into the cave.’

‘Why should she go into the cave? It is dark there and narrow and very uncomfortable.’

Rosamund said impatiently:

‘Don’t ask me for reasons. Since she was actually at the cove she was by far the most likely person. I’ve told you already I never left this place the whole morning.’

‘Except for the time when you went into the hotel to Captain Marshall’s room.’ Poirot reminded her.

‘Yes, of course. I’d forgotten that.’

Poirot said:

‘And you were wrong, Mademoiselle, when you thought that Captain Marshall did not see you.’ 

Rosamund said incredulously:

‘Kenneth did see me? Did-did he say so?’

Poirot nodded.

‘He saw you, Mademoiselle, in the mirror that hangs over the table.’

Rosamund caught her breath. She said:

‘Oh! I see.’

Poirot was no longer looking out to sea. He was looking at Rosamund Darnley’s hands as they lay folded in her lap. They were well-shaped hands, beautifully moulded with very long fingers.

Rosamund, shooting a quick look at him, followed the direction of his eyes. She said sharply:

‘What are you looking at my hands for? Do you think-do you think-?’

Poirot said:

‘Do I think-what, Mademoiselle?’

Rosamund Darnley said:

‘Nothing.’

It was perhaps an hour later that Hercule Poirot came to the top of the path leading to Gull Cove. There was someone sitting on the beach. A slight figure in a red shirt and dark blue shorts. 

Poirot descended the path, stepping carefully in his tight smart shoes.

Linda Marshall turned her head sharply. He thought that she shrank a little.

Her eyes, as he came and lowered himself gingerly to the shingle beside her, rested on him with the suspicion and alertness of a trapped animal. He realized, with a pang, how young and vulnerable she was.

She said:

‘What is it? What do you want?’

Hercule Poirot did not answer for a minute or two. Then he said:

‘The other day you told the Chief Constable that you were fond of your stepmother and that she was kind to you.’

‘Well?’

‘That was not true, was it, Mademoiselle?’

‘Yes, it was.’

Poirot said:

‘She may not have been actively unkind-that I will grant. But you were not fond of her-Oh no-I think you disliked her very much. That was very plain to see.’

Linda said:

‘Perhaps I didn’t like her very much. But one can’t say that when a person is dead. It wouldn’t be decent.’

Poirot sighed. He said: 

‘They taught you that at your school?’

‘More or less, I suppose.’

Hercule Poirot said:

‘When a person has been murdered, it is more important to be truthful than to be decent.’

Linda said:

‘I suppose youwould say a thing like that.’

‘I would say it and I do say it. It is my business, you see, to find out who killed Arlena Marshall.’

Linda muttered:

‘I want to forget it all. It’s so horrible.’

Poirot said gently:

‘But you can’t forget, can you?’

Linda said:

‘I suppose some beastly madman killed her.’

Hercule Poirot murmured:

‘No, I do not think it was quite like that.’

Linda caught her breath. She said:

‘You sound-as though youknew?’

Poirot said:

‘Perhaps I do know.’ He paused and went on: ‘Will you trust me, my child, to do the best I can for you in your bitter trouble?’

Linda sprang up. She said:

‘I haven’t any trouble. There is nothing you can do for me. I don’t know what you are talking about.’

Poirot said, watching her: 

‘I am talking aboutcandles…’

He saw the terror leap into her eyes. She cried:

‘I won’t listen to you. I won’t listen.’

She ran across the beach, swift as a young gazelle and went flying up the zigzag path.

Poirot shook his head. He looked grave and troubled.