‘That’s the cat,’ I said. ‘The identical cat I saw the first day I came here.’

Settle sniffed. An odour of bitter almonds was still perceptible.

‘Prussic acid,’ he said.

I nodded.

‘What are you thinking?’ he asked curiously.

‘What you think too!’

My surmise was no new one to him—it had passed through his brain also, I could see.

‘It’s impossible,’ he murmured. ‘Impossible! It’s against all science—all nature . . .’ His voice tailed off in a shudder. ‘That mouse last night,’ he said. ‘But—oh! it couldn’t be!’

‘Lady Carmichael,’ I said, ‘is a very strange woman. She has occult powers—hypnotic powers. Her forebears came from the East. Can we know what use she might have made of these powers over a weak lovable nature such as Arthur Carmichael’s? And remember, Settle, if Arthur Carmichael remains a hopeless imbecile, devoted to her, the whole property is practically hers and her son’s—whom you have told me she adores. And Arthur was going to be married!’

‘But what are we going to do, Carstairs?’

‘There’s nothing to be done,’ I said. ‘We’ll do our best though to stand between Lady Carmichael and vengeance.’

Lady Carmichael improved slowly. Her injuries healed themselves as well as could be expected—the scars of that terrible assault she would probably bear to the end of her life.

I had never felt more helpless. The power that defeated us was still at large, undefeated, and though quiescent for the minute we could hardly regard it as doing otherwise than biding its time. I was determined upon one thing. As soon as Lady Carmichael was well enough to be moved she must be taken away from Wolden. There was just a chance that the terrible manifestation might be unable to follow her. So the days went on.

I had fixed September 18th as the date of Lady Carmichael’s removal. It was on the morning of the 14th when the unexpected crisis arose.

I was in the library discussing details of Lady Carmichael’s case with Settle when an agitated housemaid rushed into the room.

‘Oh! sir,’ she cried. ‘Be quick! Mr Arthur—he’s fallen into the pond. He stepped on the punt and it pushed off with him, and he overbalanced and fell in! I saw it from the window.’

I waited for no more, but ran straight out of the room followed by Settle. Phyllis was just outside and had heard the maid’s story. She ran with us.

‘But you needn’t be afraid,’ she cried. ‘Arthur is a magnificent swimmer.’

I felt forebodings, however, and redoubled my pace. The surface of the pond was unruffled. The empty punt floated lazily about—but of Arthur there was no sign.

Settle pulled off his coat and his boots. ‘I’m going in,’ he said. ‘You take the boat-hook and fish about from the other punt. It’s not very deep.’

Very long the time seemed as we searched vainly. Minute followed minute. And then, just as we were despairing, we found him, and bore the apparently lifeless body of Arthur Carmichael to shore.