‘As a hospital nurse, one sees a lot of these nervous cases. Lady Grayle enjoyed her bad health. It was my part not to minimize her sufferings, to be as tactful as I could—and to enjoy the trip myself as much as possible.’

‘Very sensible,’ said Mr Parker Pyne.

‘But Mr Pyne, things are not as they were. The suffering that Lady Grayle complains of now is real and not imagined.’

‘You mean?’

‘I have come to suspect that Lady Grayle is being poisoned.’

‘Since when have you suspected this?’

‘For the past three weeks.’

‘Do you suspect—any particular person?’

Her eyes dropped. For the first time her voice lacked sincerity. ‘No.’

‘I put it to you, Miss MacNaughton, that you do suspect one particular person, and that that person is Sir George Grayle.’

‘Oh, no, no, I can’t believe it of him! He is so pathetic, so child-like. He couldn’t be a cold-blooded poisoner.’ Her voice had an anguished note in it.

‘And yet you have noticed that whenever Sir George is absent his wife is better and that her periods of illness correspond with his return.’

She did not answer.

‘What poison do you suspect? Arsenic?’

‘Something of that kind. Arsenic or antimony.’

‘And what steps have you taken?’

‘I have done my utmost to supervise what Lady Grayle eats and drinks.’

Mr Parker Pyne nodded. ‘Do you think Lady Grayle has any suspicion herself?’ he asked casually.

‘Oh, no, I’m sure she hasn’t.’

‘There you are wrong,’ said Mr Parker Pyne. ‘Lady Grayle does suspect.’

Miss MacNaughton showed her astonishment.

‘Lady Grayle is more capable of keeping a secret than you imagine,’ said Mr Parker Pyne. ‘She is a woman who knows how to keep her own counsel very well.’

‘That surprises me very much,’ said Miss MacNaughton slowly.

‘I should like to ask you one more question, Miss MacNaughton. Do you think Lady Grayle likes you?’

‘I’ve never thought about it.’

They were interrupted. Mohammed came in, his face beaming, his robes flowing behind him.

‘Lady, she hear you come back; she ask for you. She say why you not come to her?’

Elsie MacNaughton rose hurriedly. Mr Parker Pyne rose also.

‘Would a consultation early tomorrow morning suit you?’ he asked.

‘Yes, that would be the best time. Lady Grayle sleeps late. In the meantime, I shall be very careful.’

‘I think Lady Grayle will be careful too.’

Miss MacNaughton disappeared.

Mr Parker Pyne did not see Lady Grayle till just before dinner. She was sitting smoking a cigarette and burning what seemed to be a letter. She took no notice at all of him, by which he gathered that she was still offended.

After dinner he played bridge with Sir George, Pamela and Basil. Everyone seemed a little distrait, and the bridge game broke up early.

It was some hours later when Mr Parker Pyne was roused. It was Mohammed who came to him.