‘I am shocked and horrified and sickened by what I have seen this evening. My hand shakes. I can hardly bring myself to write it down. I knew, from the moment I first set eyes on her, that she was unworthy of him. One always knows. Shall not tell K. It would serve him right if I did. All these months and he never guessed. But I won’t tell him. Not yet. Not unless – But I must write it. Only so can I rid myself of the horror. I was sitting on the hill below the Spring, thinking so happily of all my plans and so glad I have settled for the shop and ordered my lovely Green Ladies. I was feeling the magic of the water. (Blessed, blessed water. No asthma, now, for four weeks.) And then I heard them. Behind the boulder, laughing. I shrank down in the bracken. And then she came out from behind the boulder in her green dress and stood above the pool. She raised her arms. I could hear the man laughing still but I couldn’t see him. I knew. I knew. The wicked desecration of it! But I won’t believe it. I’ll put it out of my mind forever. She was mocking – pretending. I won’t think anything else. She went back to him. I waited. And then, suddenly, I couldn’t bear it any longer. I came back here…’

Alleyn, looking increasingly grim, went over the entries for the whole list; throughout two summers, Miss Cost had hunted her evening quarry with obsessive devotion and had recorded the fruits of the chase as if in some antic game-book – time, place and circumstances. On each occasion that she spied upon her victims, she had found the enclosure padlocked and had taken up a point of vantage on the hillside. At no stage did she give the names of the lovers but their identity was inescapable. ‘Mrs Barrimore and Dr Maine,’ Alleyn said. ‘To hell with this case!’

‘Awkward,’ observed Fox.

‘My dear old Fox, it’s dynamite. And it fits,’ Alleyn said, staring disconsolately at his colleague. ‘The devil of it is, it fits.’

He began to read the entries for the past month. Dr Maine, Miss Cost weirdly concluded, was not to blame. He was a victim, caught in the toils, unable to free himself and therefore unable to follow his nobler inclination towards Miss Cost herself. Interlarded with furious attacks upon Miss Emily and covert allusions to the anonymous messages, were notes on the Festival, a savage comment on Miss Emily’s visit to the shop and a distracted reference to the attack of asthma that followed it. ‘The dark forces of evil that emanate from this woman’ were held responsible. There followed a number of cryptic asides: –

(‘Trehern agrees. It’s right. I know it’s right.’)

‘ “It is the Cause, it is the Cause, my soul”,’ Alleyn muttered, disconsolatedly. ‘The old, phoney argument.’