Louisa took her purse from her desk. She didn’t have time for another extended lunch hour, but how could she turn Mr. Finch down? His daughter was missing.

She slipped out without seeing her boss. Ten minutes later, she pulled out of her parking garage and turned her BMW toward the Ben Franklin Bridge, battling lunchtime traffic up Broad Street, and followed I-676 across the bridge.

Forty minutes later, she turned into a driveway marked by a rusted mailbox.

The Finches were rural poor. On the edge of a farming community, their one-story house occupied a large tract of weedy land. The roof sagged, wire fencing corralled a dozen goats, and peeling pickets protected a tidy vegetable garden. In a city-block-size cleared area behind the house, the brown remains of plants lined up in neat rows. Six cows grazed in a small, weedy pasture next to a listing barn and a scattering of ragged outbuildings.

She parked the car in a dirt rectangle next to a rusty pickup truck. Louisa opened her door and stepped out. Her heels sank in the sandy soil. A clucking sound came from the rear of the house. Chickens? Walking on her toes, she picked her way to the cracked concrete walkway that led up to the front stoop.

The door opened. The Finches stood side by side, presenting a solid front of grief.

“Please come in.” Mrs. Finch clutched a tissue in her fist. She pressed it to her nose and sniffed.

Mr. Finch, a short, balding man in his sixties, put an arm around his wife’s shoulders and ushered them into a formal living room. A flowered couch and two blue chairs surrounded a coffee table covered with papers.

Pictures of the smiling, young Zoe were everywhere. Louisa leaned over the piano and scanned a row of school pictures. She had no trouble picking Zoe out of the crowd. She was years younger and inches shorter than all of her classmates, just as Louisa had been through most of her school years.

The Finches perched on the worn couch. On his knee, Zoe’s dad held his wife’s hand between his palms. Though sick about the reason, Louisa envied the unity that emanated from the couple.

“We want to thank you for caring enough to look for Zoe, Dr. Hancock,” Mr. Finch said. “Dr. Cusack mentioned it was you who raised the alarm about Zoe being missing.”

“Please, call me Louisa.” She took one of the chairs on the opposite side of the coffee table. She leaned forward and folded her hands in her lap. “Have you heard anything from the police?”