‘Yeh, well, I want to know what it’s all about. If anyone’s going to call me names I got a right to stick up for myself, haven’t I?’

‘Perhaps I may be allowed to continue,’ said Dr Ackrington coldly.

‘For God’s sake get on with it,’ said Gaunt disgustedly. Dikon saw Barbara look wonderingly at him.

‘As I came along the verandah just now,’ said Dr Ackrington, ‘I heard you, Falls, giving a tolerably clear account of the locale. You, as the only member of our party who has had the opportunity of seeing the track, are at an advantage. If, however, your description is accurate, it seems to me there is only one conclusion to be drawn. You say Questing carried a torch and was using it. How, therefore, could he miss the place where the path has fallen in? You yourself saw it a few moments later.’

Mr Falls looked steadily at Dr Ackrington. Dikon found it impossible to interpret his expression. He had a singularly impassive face. ‘The point is quite well taken,’ he said at last.

‘The chap was half shot,’ said Simon. ‘They all say he smelt of booze. I reckon it was an accident. He went too near the edge and it caved in with him.’

‘But,’ said Dikon, ‘Mr Falls says the clod that carried away has got an impression of a nailed boot or shoe on it. Questing wore pumps. What’s the matter!’ he ejaculated. Simon, with an incoherent exclamation, had half risen. He stared at Dikon with his mouth open.

‘What the devil’s got hold of you?’ his uncle demanded.

‘Sim, dear!’

‘All right, all right. Nothing,’ said Simon and relapsed into his chair.

‘The footprint which you say you noticed, my dear Falls,’ said Dr Ackrington, ‘might have been there for some time. It may be of no significance whatever. On the other hand, and this is my contention, it may have been put there deliberately, to create a false impression.’

‘Who by?’ asked the Colonel. ‘I don’t follow all this. What did Falls see? I don’t catch what people say.’

‘Falls,’ said Dr Ackrington, ‘is it too much to ask you to put forward your theory once more?’

‘It is rather the theory which I believe the police will advance,’ said Falls. With perfect urbanity he repeated his own observations and the conclusions which he thought the police had drawn from the circumstances surrounding Questing’s disappearance. Colonel Claire listened blankly. When Falls had ended he merely said: ‘Oh, that!’ and looked faintly disgusted.