‘Hubert read me his will. He said I ought to know. He left me three thousand a year chargeable on the estate, and the dower house or the town house, whichever I preferred. Everything else he left to Diana, on condition that if she married her husband must take the name.’

‘Ah!’

‘But then he made a codicil thing–a few weeks ago, that was.’

‘Yes, madame?’

‘He still left it all to Diana, but on condition that she married Mr Barling. If she married anyone else, it was all to go to his nephew, Harry Dalehouse.’

‘But the codicil was only made a few weeks ago,’ purred Poirot. ‘Mademoiselle may not have known of that.’ He stepped forward accusingly. ‘Mademoiselle Diana, you want to marry Captain Marshall, do you not? Or is it Mr Keene?’

She walked across the room and put her arm through Marshall’s sound one.

‘Go on,’ she said.

‘I will put the case against you, mademoiselle. You loved Captain Marshall. You also loved money. Your adopted father he would never have consented to your marrying Captain Marshall, but if he dies you are fairly sure that you get everything. So you go out, you step over the flower border to the window which is open, you have with you the pistol which you have taken from the writing table drawer. You go up to your victim talking amiably. You fire. You drop the pistol by his hand, having wiped it and then pressed his fingers on it. You go out again, shaking the window till the bolt drops. You come into the house. Is that how it happened? I am asking you, mademoiselle?’

‘No,’ Diana screamed. ‘No–no!’

He looked at her, then he smiled.

‘No,’ he said, ‘it was not like that. It might have been so–it is plausible–it is possible–but it cannot have been like that for two reasons. The first reason is that you picked Michaelmas daisies at seven o’clock, the second arises from something that mademoiselle here told me.’ He turned toward Joan, who stared at him in bewilderment. He nodded encouragement.

‘But yes, mademoiselle. You told me that you hurried downstairs because you thought it was the second gong sounding, having already heard the first.’

He shot a rapid glance round the room.