‘I find it a good sign when a case is obscure. If a thing is clear as daylight—eh bien, mistrust it! Someone has made it so.’

Japp shook his head almost pityingly. ‘Well, each to their fancy. But it’s not a bad thing to see your way clear ahead.’

‘I do not see,’ murmured Poirot. ‘I shut my eyes—and think.’

Japp sighed. ‘Well, you’ve got a clear week to think in.’

‘And you will bring me any fresh developments that arise—the result of the labours of the hard-working and lynx-eyed Inspector Miller, for instance?’

‘Certainly. That’s in the bargain.’

‘Seems a shame, doesn’t it?’ said Japp to me as I accompanied him to the door. ‘Like robbing a child!’

I could not help agreeing with a smile. I was still smiling as I re-entered the room.

‘Eh bien!’ said Poirot immediately. ‘You make fun of Papa Poirot, is it not so?’ He shook his finger at me. ‘You do not trust his grey cells? Ah, do not be confused! Let us discuss this little problem—incomplete as yet, I admit, but already showing one or two points of interest.’

‘The lake!’ I said significantly.

‘And even more than the lake, the boathouse!’

I looked sidewise at Poirot. He was smiling in his most inscrutable fashion. I felt that, for the moment, it would be quite useless to question him further.

We heard nothing of Japp until the following evening, when he walked in about nine o’clock. I saw at once by his expression that he was bursting with news of some kind.

‘Eh bien, my friend,’ remarked Poirot. ‘All goes well? But do not tell me that you have discovered the body of Mr Davenheim in your lake, because I shall not believe you.’

‘We haven’t found the body, but we did find his clothes—the identical clothes he was wearing that day. What do you say to that?’

‘Any other clothes missing from the house?’

‘No, his valet was quite positive on that point. The rest of his wardrobe is intact. There’s more. We’ve arrested Lowen. One of the maids, whose business it is to fasten the bedroom windows, declares that she saw Lowen coming towards the study through the rose-garden about a quarter past six. That would be about ten minutes before he left the house.’

‘What does he himself say to that?’