“He has never mentioned it again since the day it arrived, when, as I described, he smashed it into pieces.”

“Do you know what he did with the pieces?”

“I think he may have buried them in the wood at the bottom of the garden. There is a glade in the wood, which is a favourite spot of his, where he sometimes sits on a log and smokes his pipe when he has some knotty problem to resolve. Perhaps he buried the broken tile there.”

Holmes glanced at the clock. “It is certainly an interesting case you have brought us, Miss Calloway, but one that is beset with difficulties. There are, so far as I can see, seven possible explanations for all that has occurred in and around Bluebell Cottage in the last year, although some of them are fairly unlikely. The two likeliest explanations . . .”

“Yes?”

“. . . are what I intend to concentrate on. Tell me, Miss Calloway, have you heard, from Professor Palfreyman himself, or from Mrs Wheeler or her daughter, whether there were any mysterious occurrences in previous years, before you joined the household?”

Our visitor shook her head. “Not as far as I am aware,” said she. “Mrs Wheeler had often heard the professor muttering to himself when concentrating on his work, but that is all.”

“Well,” said Holmes in a thoughtful tone. “That is suggestive, is it not?”

Miss Calloway’s features expressed surprise. “I don’t know what you mean,” she said. “I have had nothing to do with what has occurred.”

Holmes leaned over and patted her gently on the arm. “No, no, of course not,” said he. “That was not my meaning.” He lapsed into silence and remained unmoving for several minutes, a look of intense concentration upon his face, then, abruptly, he sprang to his feet. “There are some features of this case that cause me particular anxiety,” said he, “and I don’t think we should waste any time in getting down to Beckenham. The quickest way from here will be by the direct line from Victoria, I imagine.”

“Undoubtedly,” concurred Miss Calloway.

“Then that is the way we shall go. Will you come, Watson?”

“If I can be of any help to you.”

“Most certainly! Your presence may be invaluable.”

Less than thirty minutes later, we were seated in a first-class carriage as our train rumbled out of the station, across the Thames and down through the southern suburbs. Although I tried to apply my mind to the mystery Miss Calloway had brought us, I could make little of it, and could not imagine what we would do when we reached Bluebell Cottage. It was clear that Professor Palfreyman was sorely troubled by something in his past, but whether the guilt or remorse he felt was justified or not, we could not say. It was also clear that he suffered a certain degree of mental instability, but this seemed to vary considerably from one day to another, and sometimes even within the same day, and what could Sherlock Holmes, or anyone else, hope to do about that?

As we were leaving Beckenham station, a stout gentleman was approaching, who greeted Miss Calloway warmly. She introduced him to us as Professor Ainscow, introducing us simply as friends of hers.

“I’m not having the best of luck today,” he said. “I’d arranged to meet Dr Webb at Ludgate Hill station to travel down here, but although I waited an hour, he never showed up, so I came on alone. Then I walked all the way down to Bluebell Cottage, only to find that there was no one at home!” He turned as a train approached the station. “My train, I think!” he called as he hurried off. “I’ve left a large envelope for Professor Palfreyman on the front doorstep. You can’t miss it!”

There were no cabs about in the station yard, so we set off on foot at a brisk pace.

“Why is your cook, Mrs Wheeler, not at home?” Holmes asked Miss Calloway, as we walked along. “Will she have gone into Beckenham, to the shops?”

“No. She goes to visit her sister in Norwood every Wednesday morning. After getting the kitchen fire going, she left early, before breakfast, as she always does.”

“So Professor Palfreyman has been left by himself all morning?”

“Yes,” said Miss Calloway, sounding slightly amused, “but I’m sure he can cope!”

After a few minutes we turned south off the main road, down a narrow and muddy country lane, which Miss Calloway informed us was Aylmer’s Lane. A little further on, we passed two farm-worker’s cottages on our right, and then the lane entered a wood, the trees a dense screen on either side. The day had seemed only moderately foggy in the centre of Beckenham, but now, as we made our way deeper into the damp countryside, the wisps of grey mist thickened among the trees, seeming to move like wraiths as we passed by.

“Are these the woods in which you believe someone was lurking last night?” asked Holmes.

“Yes,” replied Miss Calloway, “only a little further on.”

The lane twisted and turned as it passed through the woods, until, ahead of us, we saw another lane branching off to the left.

“That is Stagg’s lane,” said Miss Calloway. “Bluebell Cottage lies about thirty yards along there on the left. And here,” she added, as we approached the corner, “is the spot where someone threw something at me.”

We turned into Stagg’s Lane, and in a few moments had reached the garden gate of the cottage. A rustic-looking man in leather gaiters was in the garden, trimming the hedge with a pair of shears.

“Hello, Perkins,” said Miss Calloway. “Have you been here long?”

“No, miss, about five minutes. There didn’t seem to be anybody at home, so I thought I’d just do what we agreed last week.”

“Very good,” said she. “I’ll speak to you again in a few minutes.”

“Did you see anyone on the road as you came down here?” Holmes asked the gardener.

“No, sir, not a soul.”

Leaning against the front door was a large manila envelope, which Miss Calloway picked up, then she unlocked the door and we followed her into the house. We waited in the hall while she went looking for the professor, but she was back in a few moments, declaring that he was nowhere about.

“Perhaps he has gone for a walk,” said she. “I have a little desk at the side of the dining room, where I deal with some of the professor’s papers,” she added, “and sometimes, when we have missed each other, he leaves a little note there for me, to tell me where he has gone. I’ll see if there’s any message today.” We followed her into the dining room, which was at the rear of the house. It was a neat little room, with a view over a long back garden. “Yes,” said Miss Calloway after a moment. “Here we are!” She picked up a folded slip of paper from the top of the desk, opened it out and read it.

“Does it say where the professor has gone?” asked Holmes.

Miss Calloway shook her head. “No,” she replied and passed the note to us.

It contained a brief message, which ran as follows:

My dear Georgina,

I have mentioned to you recently that I was writing an account of a passage in my earlier life, which I would leave for you to read when I am gone. Having finally completed it, however, I now feel that there is little point in postponing the matter, and you may as well read it now. I think you deserve an explanation for all the upsets and disturbances you have had to endure in the last year, and I hope you find the explanation satisfactory. For myself, I must say that having set it all down on paper, I feel as if a great weight has been lifted from my shoulders. Should I not be here when you wish to read it, you will find the papers in the Chinese box.

Ever yours,

James Palfreyman

“What is this Chinese box he refers to?” asked Holmes.

“It is a small chest in the professor’s study, in which he keeps his private papers. When Beryl was here, she would sometimes muddle up his papers when supposedly ‘tidying’, and he found it useful to have somewhere to keep his most important papers where Beryl could not interfere with them. The chest cannot be opened unless one knows the secret.”