She poured hot water over tea bags into slender porcelain mugs. “My mother would be shocked to see me use tea bags, or to drink my tea out of a great mug. Even when she was ninety herself, we had to get down the Crown Derby every afternoon. Mugs and tea bags feel like freedom, but I’m never sure whether it’s freedom or laxity.”

These cups, with their gold-leaf rims and intricate stencils, weren’t exactly Pacific Gardens Mission service. When Ms. Graham nodded at me to pick them up, I could hardly get my fingers into their slender handles. The tea scalded my fingers through the eggshell-thin china. Following her slow tread down the hall to her sitting room felt like some kind of biblical ordeal involving furnaces.

If Geraldine Graham had been living in a mansion like those across the street, the apartment might seem like tiny space, but the sitting room alone was about the size of my whole apartment in Chicago. Pale Chinese rugs floated on the polished wood floor. Armchairs covered in straw satin straddled a fireplace in the middle of the wall, but Ms. Graham led me to an alcove facing Larchmont Hall, where an upholstered chair stood next to a piecrust table. This seemed to be where she lived: books, reading glasses, her binoculars, a phone, covered most of the tabletop. An oil painting of a woman in Edwardian dress hung behind the chair. I studied the face for a resemblance to my hostess and her son, but it was the oval of a classic beauty. Only the coldness in the blue eyes made me think of Darraugh.

“My mother. It was a great disappointment to her that I inherited my father’s looks: she was considered the most beautiful woman in Chicago when she was young.” With her deliberate motions, Geraldine Graham moved the binoculars and glasses onto the books, then placed coasters for our mugs. Settling herself in her chair, she told me I might bring over one of those by the fireplace for myself. Her fluting voice started while I was still around the corner in the main part of the room.

“I probably shouldn’t have bought a unit facing the house. My daughter warned me I would find it hard to see strangers in the place, but of course I haven’t, except for the few months that they could afford the payments.

A computer baron who melted like snow in last year’s business upheavals. So humiliating for the children, I always think, when their horses are sold. But since they left, I haven’t seen anyone until these last few days. Nights. I see nothing out of the ordinary during the day. Although my son hasn’t said so, he seems to think I have Alzheimer’s. At least, I assume he does, since he actually drove out to visit me Thursday evening, which is a rare occurrence. I am not demented, however: I know what I’m seeing. I saw you there this afternoon, after all.”