It was some three days afterwards, when my vacation had just begun, that I received a visitor at my own apartments - a lady, heavily veiled, but evidently quite young; and I perceived at once that she was a jeune fille tout à fait comme il faut.

'You are Monsieur Hercule Poirot?' she asked in a low sweet voice.

I bowed.

'Of the detective service?'

Again I bowed. 'Be seated, I pray of you, mademoiselle,' I said.

She accepted a chair and drew aside her veil. Her face was charming, though marred with tears, and haunted as though with some poignant anxiety.

'Monsieur,' she said, 'I understand that you are now taking a vacation. Therefore you will be free to take up a private case. You understand that I do not wish to call in the police.'

I shook my head. 'I fear what you ask is impossible, mademoiselle. Even though on vacation, I am still of the police.'

She leaned forward. 'Ecoutez, monsieur. All that I ask of you is to investigate. The result of your investigations you are at perfect liberty to report to the police. If what I believe to be true is true, we shall need all the machinery of the law.'

That placed a somewhat different complexion on the matter, and I placed myself at her service without more ado.

A slight colour rose in her cheeks. 'I thank you, monsieur. It is the death of M. Paul Déroulard that I ask you to investigate.'

'Comment?' I exclaimed, surprised.

'Monsieur, I have nothing to go upon - nothing but my woman's instinct, but I am convinced - convinced, I tell you - that M. Déroulard did not die a natural death!'

'But surely the doctors -'

'Doctors may be mistaken. He was so robust, so strong. Ah, Monsieur Poirot, I beseech of you to help me -'

The poor child was almost beside herself. She would have knelt to me. I soothed her as best I could.

'I will help you, mademoiselle. I feel almost sure that your fears are unfounded, but we will see. First, I will ask you to describe to me the inmates of the house.'

'There are the domestics, of course, Jeanette, Félicie, and Denise the cook. She has been there many years; the others are simple country girls. Also there is François, but he too is an old servant. Then there is Monsieur Déroulard's mother who lived with him, and myself. My name is Virginie Mesnard. I am a poor cousin of the late Madame Déroulard, M. Paul's wife, and I have been a member of their ménage for over three years. I have now described to you the household. There were also two guests staying in the house.'

'And they were?'

'M. de Saint Alard, a neighbour of M. Déroulard's in France. Also an English friend, Mr John Wilson.'

'Are they still with you?'

'Mr Wilson, yes, but M. de Saint Alard departed yesterday.'

'And what is your plan, Mademoiselle Mesnard?'