Forty minutes out of Las Vegas, high over Utah, above the weather and bound for Colorado, Ryan excused himself and went to the lavatory.

He dropped to his knees and threw up in the toilet. He had developed a nervous stomach awaiting takeoff, and it had grown worse in flight.

At the sink, he rinsed out his mouth twice and washed his hands. He was struck by the paleness of his fingers, as white as bone.

When he looked at his face in the mirror, he found that it was paler than his hands, his lips without color.

Reluctantly he met his eyes and for some reason thought of Alvin Clemm and the convenient stepladder, the convenient concrete, the silk scarf and the convenient heart attack.

His legs grew weak, and he sat on the toilet. His hands were shaking. He clasped them, hoping one would steady the other.

He didn’t know when he had gotten up to wash his hands again. He found himself at the sink, scrubbing.

He was sitting on the toilet again when he heard a rapping, which quickened his heart until he realized this really was a hand upon a door.

“Are you all right?” asked Cathy Sienna.

“I’m sorry,” he said. “Yes. I’m sorry.”

“You’re okay?”

“A little airsickness,” he explained.

“Do you need anything?”

“Just a minute. Give me a minute.”

She went away.

Airsickness wasn’t the correct diagnosis. He was sick with fear about what he would find on the ground, in Denver, in the house of Ismena Moon, which had once been the house of Ismay.

Leaving stars behind, and moon, they descended through deep clouds, a white boil at the portholes, and then Denver appeared below, sparkling in the clear night air.

In flight, Ryan had phoned Ismena, telling her only that her late sister had done a kindness for him that he’d never forgotten and, as he was in Denver, he would like to stop by and find out more about Ismay. After Ismena welcomed their visit, Ryan had arranged for a Cadillac Escalade, which awaited them at the airport.

The January night was so bleak that his cold hands felt warm by comparison. His breath plumed from him, curls of vapor lingering for brief moments before deliquescing into the still air.

His stomach was settled, but not his nerves, and after they put their two small pieces of luggage in the back of the Escalade, he asked Cathy Sienna to drive. In the passenger seat, he read Ismena’s address from a notepad on which he had written it, and Cathy keyed it into the navigator.

She drove well, handling the big SUV as if she had put fifty thousand miles on it before this. Ryan suspected that she was good not merely with a gun and a car but also with just about any machine or tool, good with things because she preferred them to people.

The very act of driving brought a slight unconscious smile to her. Although she usually guarded her expressions closely, her face was not a mask at this moment, but relaxed as Ryan had not before seen it.

“Do I need to know who this woman is, why we’re here?” she asked.

He told her only about Ismay Clemm’s kindness to him during the myocardial biopsy-and then that he had this day learned the nurse had died twenty-one months before he met her.

Of the reactions he expected from Cathy, she exhibited none. The faint smile remained, and she kept her eyes on the road, as if he had said nothing more surprising than that, judging by the lowering sky, snow would soon fall.

“Twenty-one months. What do you make of that?” she asked.

“Ismena and Ismay are identical twins.”

“So you-what?-think it was Ismena at the biopsy?”

“Maybe. Probably.”

“But she was using Ismay’s name? Why would she?”

“That’s one thing I want to find out.”

“I guess you would.”

He waited for her to say something more. She drove in silence, and only spoke to say “Yes, ma’am,” each time the computerized voice of the navigation system gave her an instruction.

For her line of work, Cathy had been trained to listen carefully to what a client needed to tell her about his problems and to have no curiosity about any portion of his story that he failed to disclose. But her ability to feign disinterest in this case seemed almost superhuman.

As the navigator announced a final turn to the left coming in three hundred yards, Ryan recognized the park with the aspen trees and the church beside it.

“Pull over,” he said. “I know this place. If her house is just around the corner, we can walk from here.”

Their jackets were not heavy enough for the weather, but the air remained still, with no wind-chill factor. Hands in their pockets, they walked first into the park.

The aspens had shed their leaves for winter. The smooth bare limbs described pale geometries against the night sky.

A recent snow, not yet despoiled by children’s boots, mantled the grass, and the brick walkways wound like channels of dark water through the whiteness.

“I was here once,” he told Cathy, “sixteen months ago.”

She walked with him and waited.

“That time, I had the most powerful experience of deja vu. The air was as still then as now, but the aspens were whispering, as they always do when they’re leafed out. And I thought how much I’d always loved that sound-and then realized I’d never heard it before.”

A lamppost spilled light upon an iron bench. Icicles depended from the front skirt of the bench, and ice glazed the bricks directly under them.

“Sitting on this bench, I became convinced I’d sat here many times in the past, in all seasons and kinds of weather. And I felt the most powerful nostalgic sense of…of love for this place. Strange, don’t you think?”

Again surprising him, she said, “Not really.”

Ryan looked at her. Aware of his stare, she did not return it.

“Are you experiencing any of that now?” she asked, gazing up into the aspen architecture.

Shivering, Ryan surveyed the park. “No. It’s just a place this time.”

They walked to the front steps of St. Gemma’s Church, where a bronze lamp in the shape of a bell brightened the oak doors.

“I knew what the church would look like before I went inside. And when I went in…I felt I’d returned to a much-loved place.”

“Should we pay a visit?”

Although he knew he could not have been located and followed to Colorado so quickly, Ryan imagined that if he went into the church, he would find waiting for him the woman with the lilies and the knife, this time without the lilies.

“No,” he said. “It won’t feel special now. It’ll be like the park-just a place.”

His ear lobes began to sting with cold, his eyes watered, and the icy air had a faint ammonia scent that burned in his nostrils.

On the opposite side of the church from the aspen grove lay an expansive cemetery. No fence encircled it, and lampposts flanked a central walk.

“I didn’t see this before,” he said. “I didn’t come this far. When I left the church, I was so…spooked, I guess, I just wanted to get back to the hotel. I thought I’d been poisoned.”

This statement seemed to strike Cathy Sienna as more peculiar than anything else that he had revealed. As they walked past the cemetery toward the corner, she was first silent, but then said, “Poisoned?”

“Poisoned or drugged with hallucinogenics. It’s a long story.”

“No matter how long it is, seems to me poisoned-and-drugged is a bigger leap than some other explanation.”

“What other explanation?”

She shrugged. “Whatever other explanation you didn’t want to consider.”

Her answer disturbed Ryan, and suddenly so did the graveyard.

“I’ll bet she’s buried here,” he said.

“You mean Ismay Clemm?”