'Excellent, Woodie, excellent. A full case, well presented, and dependent on inference and circumstantial evidence.'

'Oh,' said the secretary, disappointed. 'Have I missed something?'

'No, nothing. Royden Sharp is our man, there's not the slightest doubt about it in my mind. But we need more concrete proof. In particular, we need the horse lancet. We need to secure it. Sharp knows we're in the district, and if he's any sense it will already have been thrown into the deepest lake he knows.'

'And if it hasn't?'

'If it hasn't, then you and Harry Charlesworth are going to stumble across it and secure it.'

'Stumble?'

'Stumble.'

'And secure it?'

'Indeed.'

'Have you any suggestions about our modus operandi?'

'Frankly, I think it would be better if I didn't know too much. But I imagine that it is still the custom in these parts of the country for people to leave their doors unlocked. And if it turns out to be a matter of negotiation, then I would suggest that the sum involved appear in the accounts for Undershaw in whichever column you choose to put it.'

Wood was rather irritated by this high-mindedness. 'Sharp is hardly likely to hand it over if we knock on his door and say, Excuse us, may we please buy the lancet you ripped the animals with, so that we can show it to the police?'

'No, I agree,' said Arthur with a chuckle. 'That would never do. You will need to be more imaginative, the two of you. A little more subtlety. Or, for that matter, a little more directness. One of you might distract him, perhaps in a public house, while the other… She did mention a cupboard in the kitchen, did she not? But really, I must leave it to you.'

'You will stand bail for me if required?'

'I will even give you a character witness.'

Wood shook his head slowly. 'I still can't get over it. This time last night we knew almost nothing. Or rather, we had a few suspicions. Now we know everything. All in a day. Wynn, Greatorex, Mrs Greatorex – and that's it. We may not be able to prove it, but we know it. And all in a day.'

'It's not meant to happen like this,' said Arthur. 'I should know. I've written it enough times. It's not meant to happen by following simple steps. It's meant to seem utterly insoluble right up until the end. And then you unravel the knot with one glorious piece of deduction, something entirely logical yet quite astounding, and then you feel a great sense of triumph.'

'Which you don't?'

'Now? No, I feel almost disappointed. Indeed, I do feel disappointed.'

'Well,' said Wood, 'you must permit a simpler soul a sense of triumph.'

'Willingly.'

Later, when Arthur had smoked his final pipe and turned in, he lay in bed reflecting on this. He had set himself a challenge, and today he had overcome it; yet he felt no exultation. Pride, perhaps, and that certain warmth when you take a rest from labour, but not happiness, let alone triumph.

He remembered the day he had married Touie. He had loved her, of course, and in that early stage doted on her entirely and could not wait for the marriage's consummation. But when they wed, at Thornton-in-Lonsdale with that fellow Waller at his elbow, he had felt a sense of… how could he put it without being disrespectful to her memory? He was happy only insofar as she had looked happy. That was the truth. Of course, later, as little as a day or two later, he began to experience the happiness he had hoped for. But at the moment itself, much less than he had anticipated.

Perhaps this was why, at every turn in his life, he had always sought a new challenge. A new cause, a new campaign – because he was only capable of brief joy at the success of the previous one. At moments like this, he envied Woodie's simplicity; he envied those capable of resting on their laurels. But this had never been his way.

And so, what remained to be done now? The lancet must be secured. A specimen of Royden Sharp's handwriting must be obtained – perhaps from Mr and Mrs Greatorex. He must see if Walker and Gladwin had any further relevance. There was the matter of the woman and child who were attacked. Royden Sharp's scholastic career at Walsall must be investigated. He must try to match Wallie Sharp's movements more specifically to places from which letters had been posted. He must show the horse lancet, once secured, to veterinary surgeons who had attended the injured animals, and ask for their professional evaluation. He must ask George what, if anything, he remembered of the Sharps.

He must write to the Mam. He must write to Jean.

Now that his head was full of tasks, he descended into untroubled sleep.

Back at Undershaw, Arthur felt as he did when nearing the end of a book: most of it was in place, the main thrill of creation was past, now it was just a matter of work, of making the thing as watertight as possible. Over the next days the results of his instructions, queries and proddings began to arrive. The first came in the form of a waxed brown-paper parcel tied with string, like a purchase from Brookes's ironmongery. But he knew what it was before he opened it; he knew from Wood's face.

He unwrapped the parcel, and slowly opened the horse lancet out to its full length. It was a vicious instrument, made the more so by the contrast between the bluntness of the straight section and the honed edge on the lethal curve – which was indeed as sharp as sharp could be.

'Bestial,' said Arthur. 'May I ask-'

But his secretary cut off the enquiry with a shake of the head. Sir Arthur couldn't have it both ways, first not knowing and then choosing to know.

George Edalji wrote to say that he had no memory of the Sharp brothers, either at school or subsequently; nor could he think of a reason why they might bear any animus against himself or his father.

More satisfactory was a letter from Mr Mitchell detailing Royden Sharp's scholastic record:

Xmas, 1890. Lower 1. Order, 23rd out of 23. Very backward and weak. French and Latin not attempted.

Easter, 1891. Lower 1. Order, 20th out of 20. Dull, homework neglected, begins to improve in Drawing.

Midsummer, 1891. Lower 1. Order, 18th out of 18. Beginning to progress, caned for misbehaviour in class, tobacco chewing, prevarication, and nicknaming.

Xmas, 1891. Lower 1. Order, 16th out of 16. Unsatisfactory, often untruthful. Always complaining or being complained of. Detected cheating, and frequently absent without leave. Drawing improved.

Easter, 1892. Form 1. Order, 8th out of 8. Idle and mischievous, caned daily, wrote to father, falsified school-fellows' marks, and lied deliberately about it. Caned 20 times this term.

Midsummer, 1892. Played truant, forged letters and initials, removed by his father.

There we are, thought Arthur: forging, cheating, lying, nicknaming, general mischief. And further, note the date of the expulsion or removal, whichever you prefer: Midsummer 1892. That was when the campaign had begun, against the Edaljis, against Brookes and against Walsall School. Arthur felt his irritation rising – that he could find such things out by a normal process of logical inquiry, whereas those dunderheads… He would like to set the Staffordshire Constabulary up against a wall, from the Chief Constable and Superintendent Barrett through Inspector Campbell and Sergeants Parsons and Upton down to the humblest novice in the force, and ask them a simple question. In December 1892 a large key belonging to Walsall School was stolen from the premises and transported to Great Wyrley. Who might be the more plausible suspect: a boy who a few months previously had been ignominiously removed from the school after a career there of stupidity and malice; or the studious and academically promising son of a Vicar, who had never attended Walsall School, never visited its premises, and bore no more grudge against the establishment than did the Man in the Moon? Answer me that, Chief Constable, Superintendent, Inspector, Sergeant and PC Cooper. Answer me that, you twelve good men and true at the Court of Quarter Sessions.