The body had already been removed by the time Sloane Mercer reached the twelfth floor.

She knew before the elevator doors opened. The hallway was too quiet, the way a corridor is quiet after it has just been emptied and someone intends to keep it that way. Two men in dark coats stood at the entrance to the apartment. Neither of them looked at her face as she approached. They simply stepped aside.

That was the first wrong thing.

The second was the smell. Mayfair apartments at this price point smelled of nothing. That was what you paid for. This one smelled of cleaning solvent. Recent. The kind a building’s service team used in the half hour between a problem ending and the building deciding the problem had never existed.

Sloane stopped just inside the doorway, gloves still on.

The apartment was beautiful in the way Mayfair apartments were always beautiful: high coffered ceilings, wide oak floors bleached to a bone-pale gray, floor-to-ceiling windows holding a careful slice of Hyde Park. Nothing on the surfaces. Nothing out of alignment. The kitchen, visible through the open archway, looked the way a kitchen looks when no one has ever actually cooked in it.

A man cleared his throat behind her. Mid-forties. Building staff, by his coat. A voice that had practiced sounding helpful.

“Ms. Mercer?”

“Give me a minute.”

She did not turn. She stood in the threshold and let the room finish settling.

There was a faint compression in the rug fibers beside the sofa. Weight had rested there long enough to leave a mark. A side table sat a degree off the line of the sofa, which meant someone had brushed it recently and corrected it imperfectly. The marble counter in the kitchen had been wiped, but not in the pattern of a routine cleaning. It had been wiped the way you wipe a counter when you want one specific area cleaner than the rest.

A man had died in this room within the last six hours. He had died near the sofa. He had died without a struggle. And then a very disciplined group of people had spent ninety minutes turning the room back into a brochure.

“Cause of death?” Sloane asked, still facing the room.

“Preliminary is overdose, Ms. Mercer.”

“And what exactly was found on him?”

A beat. “Nothing.”

She let the word sit. Most people, even professionals, would have filled the silence after it. The man behind her did not, which was an unhelpful kind of competence.

“A man who keeps an apartment this disciplined,” she said quietly, “does not lose control thoroughly enough to die, and then keep enough composure to dispose of the evidence before his heart stops.”

She heard him shift his weight. He did not answer.

Sloane removed her gloves and slid them into her coat pocket. She crossed to the windows. Below, the park had gone the flat green-gray of a London afternoon. Joggers, nannies, and dog walkers moved along the paths as if nothing of consequence had ever happened in a building like this one.

Her phone vibrated once against her hip. She ignored it.

A thin rain had begun against the glass, the slow, indecisive London rain that never fully committed and never fully stopped. On the street below, a black sedan idled at the curb. She watched it for a long moment without moving her head.

Then she watched it pull away.

It had not been waiting for a passenger. It had been waiting to see her enter the building.

She let her hand rest against the cold glass. She had stood inside disciplined deaths before. She had seen rooms cleaned. This was the cleanest one she had ever stood inside.

She turned and looked at the man in the doorway. He waited with the patient blankness of someone who had been told not to comment on whatever she did next.

“Who called it in?”

“His firm. A morning wellness check.”

“Door locked?”

“Double-locked from the inside. The smart system shows no entries after eight last night.”

She nodded once. From the inside pocket of her coat she took the short lead pencil she always carried, because pencil could be erased and ink could be subpoenaed. She flipped open the legal pad in her left hand.

At the top of a fresh page, she wrote four words in stark, ungenerous block letters.

THIS DEATH WAS INTRODUCED.

She underlined the last word.

Then she closed the pad, walked back into the room, and began.