My chair, comically, was too low. I sat there sunk in the thing with my knees halfway up my chest, while the head loomed over me.

She didn’t remember Gina—in fact, Ms. Gisborne was actually about the same age as my older sister—but she had taken the trouble to find some of her reports. “She came over well: a bright, pretty girl, natural leader . . .” The kind of thing people had always said of Gina. But she held out little hope of tracing any record of any younger sister, and clearly thought it odd that I should even be asking. “There was a preschool department here in those days—for the under-fives, you understand—but it has long since closed down. The school’s gone through a lot of changes since then. I’ll see if Milly can find the records, but I’m not optimistic. It’s all so long ago—no offense!”

“None taken.”

While we were waiting for the secretary to go down into the dungeons, Ms. Gisborne offered me the choice of a coffee, or a quick tour of the school. I felt restless, embarrassed, foolish, and I knew I would quickly run out of conversation with the headmistress of a Catholic school. I chose the tour. I had a little trouble hauling my bulk out of the tiny chair.

Out we walked.

The school was a place of layered history. A frame of two-story Victorian-era buildings enclosed a small grassy quadrangle. “We encourage the students to play croquet in the summer,” said Ms. Gisborne lightly. “Impresses the Oxbridge interviewers.” The corridors were narrow, the floor hardwood with dirt deeply ground in. There were immense, heroic radiators; huge heating pipes ran beneath the ceiling. We walked past classrooms. Behind thick windows rows of students, some in blue blazers, labored at unidentifiable tasks.

“It all reminds me of my own school,” I said uncomfortably.

“I know how you feel; many parents of your generation feel the same. Narrow corridors. Oppressive ceilings.” She sighed. “Doesn’t create the right atmosphere, but not much we can do short of pulling it all down.”

We passed out of the central block. The peripheral buildings were newer, dating from the fifties through to more recent times. I was shown a custom-built library constructed in the eighties, a bright and attractive building within which there seemed to be as many computer terminals as bookshelves. The students worked steadily enough, so far as I could see, though no doubt the presence of the head was an encouragement.