‘My train, I fear, was late,’ said M. Poirot. ‘An accident on the line in front of us.’

‘Oh,’ cried Joan, ‘so that’s why dinner was put off.’

His eye came quickly round to her–a most uncannily discerning eye.

‘That is something out of the usual–eh?’

‘I really can’t think–’ began Mrs Lytcham Roche, and then stopped. ‘I mean,’ she went on confusedly, ‘it’s so odd. Hubert never–’

Poirot’s eyes swept rapidly round the group.

‘M. Lytcham Roche is not down yet?’

‘No, and it’s so extraordinary–’ She looked appealingly at Geoffrey Keene.

‘Mr Lytcham Roche is the soul of punctuality,’ explained Keene. ‘He has not been late for dinner for–well, I don’t know that he was ever late before.’

To a stranger the situation must have been ludicrous–the perturbed faces and the general consternation.

‘I know,’ said Mrs Lytcham Roche with the air of one solving a problem. ‘I shall ring for Digby.’

She suited the action to the word.

The butler came promptly.

‘Digby,’ said Mrs Lytcham Roche, ‘your master. Is he–’

As was customary with her, she did not finish her sentence. It was clear that the butler did not expect her to do so. He replied promptly and with understanding.

‘Mr Lytcham Roche came down at five minutes to eight and went into the study, madam.’

‘Oh!’ She paused. ‘You don’t think–I mean–he heard the gong?’

‘I think he must have–the gong is immediately outside the study door.’

‘Yes, of course, of course,’ said Mrs Lytcham Roche more vaguely than ever.

‘Shall I inform him, madam, that dinner is ready?’

‘Oh, thank you, Digby. Yes, I think–yes, yes, I should.’

‘I don’t know,’ said Mrs Lytcham Roche to her guests as the butler withdrew, ‘what I would do without Digby!’

A pause followed.

Then Digby re-entered the room. His breath was coming a little faster than is considered good form in a butler.

‘Excuse me, madam–the study door is locked.’

It was then that M. Hercule Poirot took command of the situation.

‘I think,’ he said, ‘that we had better go to the study.’

He led the way and everyone followed. His assumption of authority seemed perfectly natural. he was no longer a rather comic-looking guest. He was a personality and master of the situation.

He led the way out into the hall, past the staircase, past the great clock, past the recess in which stood the gong. Exactly opposite that recess was a closed door.

He tapped on it, first gently, then with increasing violence. But there was no reply. Very nimbly he dropped to his knees and applied his eye to the keyhole. He rose and looked round.

‘Messieurs,’ he said, ‘we must break open this door. Immediately!’