Summary. It was Nan Pringle, and for money that was about to stop being hers — here is how I came to it.

The Reckoning. The Colonel died of a fall, and the fall wants no explaining: the gallery rail was out for mending, the gap sheeted over and black as pitch in the dark, and any man who walked that passage without a light would go through it. The question was never how he died. It was who sent him up that passage, and why, on that particular Tuesday, with a new will drawn Monday and standing to be signed Wednesday at eleven. I have been to this house before on lighter business than a corpse, and I confess I expected to be back; I did not expect it quite so soon.

The note did the work. Four words, in Nan's own hand, telling the Colonel that the man he had spent a week vowing to catch was upstairs now. He rose without a word, took his stick and a candle, and went up quietly to surprise a prowler who was not there — for Captain Frew was at that hour in the yard with his pipe, under Mrs Gow's eye at the scullery door, exactly where he had been every night that week, and exactly where Nan alone had arranged, that same afternoon, for him to be. She keeps the Colonel's engagements. She had passed the word to the kitchen herself. No one else in that house could have written a note naming Frew and be certain, past all accident, that Frew would be found innocent of it and safely elsewhere.

The rest fall away for want of opportunity or want of knowledge. Fifi was belowstairs laying trays with Mrs Gow from a quarter to nine, in that lady's sight the whole while, and no notice had ever been given her over the business of the hat — there was nothing pending against her that Tuesday, whatever the Colonel's temper on the Saturday before. Aziz sat at the end of the front row beside Xerxes for the full twenty minutes, placed there by two witnesses who had no reason to agree falsely, and never came near the Colonel's chair. Frew is the man the note names, and a man does not write a lure pointing at himself and then stand where the housekeeper can watch him do it. Cousin R sat directly behind the Colonel throughout — it is his account, in fact, that fixes the rising at five minutes past nine — but he could not have known Frew would be in the yard at all; that word went nowhere but to the kitchen, and Nan carried it.

The motive is not complicated, only unlovely. Nan is the Colonel's dependent niece, eleven years in that house without wages, her allowance counted into her hand before the assembled family like a child's pocket-money. Under the standing will she takes half the residue with Effie Strange. Under the instrument drawn on the Monday — and the Colonel's remark at dinner left little doubt which way it leaned — she would have taken nothing. She had one clear day between the drawing of the new will and its signing. She used it. The note cost her nothing to write and nothing to be traced to, since she owned it at once as referring, innocently, to Frew; it was only the arithmetic of the evening — who was where, and who alone could have arranged for Frew to be blamelessly in the yard — that turned an ordinary domestic accident into a woman's hand on a dead man's fortune. I had very nearly let that afternoon's word to the kitchen pass as housekeeping. It was the whole of the case.

She sat in her chair the entire twenty minutes and never rose, and did not need to. I am charging her with the Colonel's murder, the third this twelvemonth, by my count, and glad enough to have the file closed, though not, in this house, for long.

When all's said and counted, the deed it was done,
and Nan the answer, when answer was none.
Poor the Colonel lies quiet, a candle, a knife,
the tidiest exit from Cairnholm and life.
The lesson is here, should we trouble to learn —
but the cards, being cards, will be dealt a fresh turn.