Of course, I knew at once by the expression of her face that morning that my dear lady had some important business on hand. She had a bundle in her arms, consisting of a shabby-looking coat and skirt, and a very dowdy hat trimmed with bunches of cheap, calico roses. “Put on these things at once, Mary,” she said curtly, “for you are going to apply for the situation of ‘good plain cook,’ so mind you look the part.” “But where in the world----?” I gasped in astonishment. “In the house of Mr. Nicholas Jones, in Eaton Terrace,” she interrupted dryly, “the one occupied until recently by his sister, the late Mrs. Dunstan. Mrs. Jones is advertising for a cook, and you must get that place.” As you know, I have carried obedience to the level of a fine art. Nor was I altogether astonished that my dear lady had at last been asked to put one of her dainty fingers in that Dunstan pie, which was puzzling our fellows more completely than any other case I have ever known. I don’t know if you remember the many circumstances, the various contradictions which were cropping up at every turn, and which baffled our ablest detectives at the very moment when they thought themselves most near the solution of that strange mystery. Mrs. Dunstan herself was a very uninteresting individual: self-righteous, self-conscious and fat, a perfect type of the moneyed middle-class woman whose balance at the local bank is invariably heavier than that of her neighbours. Her niece, Violet Frostwicke, lived with her: a smart, pretty girl, inordinately fond of dainty clothes and other luxuries which money can give. Being totally impecunious herself, she bore with the older woman’s constantly varying caprices with almost angelic patience, a fact probably attributable to Mrs. Dunstan’s testamentary intentions, which, as she often averred, were in favour of her niece. In addition to these two ladies, the household consisted of three servants and Miss Cruikshank. The latter was a quiet, unassuming girl who was by way of being secretary and lady-help to Mrs. Dunstan, but who, in reality, was nothing but a willing drudge. Up betimes in the morning, she combined the work of a housekeeper with that of an upper servant. She interviewed the tradespeople, kept the servants in order, and ironed and smartened up Miss Violet’s blouses. A Cinderella, in fact. Mrs. Dunstan kept a cook and two maids, all of whom had been with her for years. In addition to these, a charwoman came very early in the morning to light fires, clean boots, and do the front steps.