The invitation arrived on a Tuesday, which was unfortunate because Tuesdays in 1925 were supposed to be ordinary days. Jay Calloway had built his reputation on the belief that there was nothing ordinary about a Tuesday, but even he had to concede that this particular Tuesday smelled faintly of the previous night's champagne and carried the dull throb of a hangover that no amount of black coffee could touch.

The invitation was cream-colored, heavy stock, with letters in a script so ornate it looked like it had been drawn by someone who believed that readability was a form of vulgarity. It announced a party. Not just any party—a gathering, as the invitation delicately put it, "for those who understand that time is not a river but a room, and that we have discovered the key."

Jay set the invitation on his desk and stared at it. The desk was mahogany, a relic from his father's generation, and it had survived the crash of '22, the dry-cleaning scandals, and three separate attempts by his partners to dilute his ownership stake. It was a solid thing in an era that seemed determined to convince everyone that solidity was outdated.

"You're going," said Zelda Montgomery from the doorway. She was leaning against the frame with the practiced nonchalance of a woman who had spent the better part of a decade learning how to occupy space without apologizing for it. Her dress was blue, the particular shade of blue that existed only in the moments between dusk and night, and her hair was cut in a style that made her look either seventeen or forty depending on the angle of the light.

"I'm considering it," Jay said.

"Considering is just another word for wanting something you're afraid to admit you want."

Jay looked at her. Zelda had always been dangerously perceptive, which was one of the reasons he had fallen in love with her and another reason he had married her and a third reason he was not entirely sure he wanted to stay married to her once the novelty of her perception wore off—which it inevitably did, as all novel things did in the long, slow erosion of American prosperity.

"What kind of party is it?" he asked.

Zelda crossed the room and picked up the invitation. She held it between two fingers as though it might be contaminated. "They're calling it the Fountain Party. A man named Harrington is hosting it. He's got money—old money, the kind that comes from railroads and steel and men who shook hands with Roosevelt and thought they were helping him."

"Old money doesn't do fountains," Jay said. "Old money does monuments."

"This old money does fountains," Zelda said. "Apparently, Harrington has been visiting a man in Switzerland. A doctor, or an alchemist, or something. The invitation uses the word interchangeably. The man has developed a treatment. A substance. Something that extends life. Not youth—life. The distinction, apparently, is important."

Jay felt the familiar pull in his chest, the one he had been fighting for months. It was not vanity, he told himself. Vanity was for women and actors and men who wore pink suits in July. This was something deeper, something more fundamental. It was the realization that he was thirty-six years old and already felt the beginning of the long decline, the slow creep of fatigue that no amount of sleeping or scotch or Zelda's blue dresses could quite reach.

"How much?" he asked.

Zelda's eyes narrowed. "How much what?"

"How much does the fountain cost?"

"Five hundred thousand dollars."

Jay whistled softly. That was not old money. That was not even new money. That was the kind of money that belonged to men who owned islands.

"Is that for the full treatment?" he asked.

"For the first dose," Zelda said. "They say it has to be administered in stages. Like building a house. You lay the foundation before you put up the walls."

Jay looked out the window. Below him, Fifth Avenue was a river of Model Ts and taxis and men in hats who looked like they had been cut from a newspaper and pasted onto the sidewalk. They were all moving somewhere, all of them, and none of them were moving fast enough.

"Who else is going?" he asked.

Zelda consulted a second piece of paper, a guest list she had clearly obtained through means she was not prepared to discuss. "Harrington, of course. The Vanderbeeks. The Whitneys. A man named Sterling who flew across the Atlantic last month and is currently the most popular man in New York. And—" she paused, "—a woman named Gerta Weissman. She's German. She says the treatment works the same everywhere, that time does not discriminate by nationality."

Jay laughed, and the laugh came out sharper than he intended. "Time doesn't discriminate. That's the whole point, isn't it? Time is the only thing we all share, the only thing that's truly equal, and these people are trying to buy their way out of it."

"Are you one of 'these people,' Jay?"

He did not answer. He could not answer. Because the truth was that he had been thinking about the treatment every day for three months, that he had calculated the numbers until they were etched into his mind like prayer beads, that he had imagined himself at fifty and sixty and eighty and one hundred, walking through rooms full of people who were his grandchildren and his grandchildren's grandchildren, still standing, still speaking, still present in a world that had moved on without everyone he had ever loved.

It was not vanity. It was not even fear. It was something simpler and more terrible: it was the refusal to disappear.

"Tell me you would come with me," he said to Zelda.

She was quiet for a long time. The party invitations were piling up on his desk, each one more ornate than the last, each one a small golden key to a door he was not sure he wanted to walk through. Outside, a saxophone was playing somewhere, the sound drifting up from a speakeasy on the corner, the music bright and desperate and full of a joy that knew it would not last.

"I would come with you," Zelda said, "to the party. I would drink the champagne and dance with the men who own the railroads and the men who flew across the Atlantic and the man from Switzerland who thinks he has conquered time. And then I would come home with you, and I would sit on the fire escape, and I would watch the sun come up over Manhattan, and I would be twenty-seven years old instead of twenty-six, and you would be thirty-six instead of thirty-five, and we would have one more day, and then one more, and then one more."

She set the invitation down next to his.

"But Jay," she said, "how many more would be enough? How many more days, how many more years, how many more sunrises over a city that will never love you the way you love it, before you realize that you have bought yourself a room full of time and emptied yourself of everything that makes time worth filling?"

Jay looked at the invitation. He looked at Zelda. He looked at the saxophone player, whose music had stopped and who was now lighting a cigarette with hands that shook slightly, from the cold or from the music or from the simple fact of being alive in a world that demanded everything and gave back almost nothing.

"I don't know," Jay said.

And the truth was, neither of them knew. Neither of them would know until it was too late, or perhaps not even then, because some questions do not have answers. They only have the long, slow process of living them out, one day at a time, one sunrise at a time, one sip of champagne at a time, until the champagne runs out and the music stops and the room is empty and you are alone with the key in your hand and the door behind you and the long corridor stretching forward into a future you purchased but did not earn.