“How have you been, Ada? How’s David?” asked Hayato, kindly.
“Okay,” said Ada. Against her will she felt a tremble in her chin. And she realized that she felt betrayed by not just Liston, but all of them, all of them. Her friends. Something like her family. Where had they been?
The three of them glanced at each other. They were sitting across the table from her, three in a row, so that she felt as if they were interviewing her.
“I’m sorry we haven’t been in touch,” said Frank. “We just—weren’t sure how to react, in light of . . .”
“It’s okay,” Ada said again. She did not want to hear what they had to say. She had not yet taken her jacket off, her blue ski parka, and it was making her warm. It bunched up around her shoulders as she sat against the hard back of the chair. In her pocket, she touched the four corners of the floppy disk she had brought with her. It was one of the copies she had made. The original disk that David had given her was still at Liston’s, in its dictionary, for safekeeping.
She explained her request straightforwardly, and all three of them sat up with interest. She could have predicted it: this group had always loved a puzzle.
“When did David give it to you?” asked Hayato.
“Over two years ago,” said Ada. “The night after the last grad-student dinner he hosted.”
She held it out, and Hayato accepted it. If anyone could decrypt it, it was Hayato: he and David had shared a love of puzzles and codes, had tried, over the years, to stump each other dozens of times. Neither had ever been successful. Often a triumphant shout would come from one or the other of their offices, toward the end of a workday, and the other would rush in to inspect the solution. “Eureka!” Liston would say sarcastically. “Do they ever work?”
The four of them migrated to the computer in the corner, which started up with a speed that surprised Ada. It was Apple’s latest model: in the time since David’s retirement, the world of technology had already, she thought, left her behind.
She double-clicked the icon of the text file and it opened to display its contents, the single string of letters:
DHARSNELXRHQHLTWJFOLKTWDURSZJZCMILWFTALVUHVZRDLDEYIXQ.
Silence.
“That’s it?” said Charles-Robert. “Just that text file?”
“That’s it,” said Ada.
“What did he say when he gave it to you?” asked Frank.
“He said it was a puzzle,” said Ada. “He said it was solvable, but it might take some time to figure out. And that I shouldn’t let it get in the way of my other work.”
“Hmmm,” said Hayato. All three of them were leaning down behind her, reading over her shoulders. Ada could feel their interest: already their eyes were scanning it, looking for patterns, for inconsistencies, for the frequency of each letter.
“Why didn’t he just write it down on a piece of paper?” asked Charles-Robert. “Why put something so short on a disk?”
“I don’t know,” said Ada. “To protect it?” But it was a good question: one she had wondered about as well.
Ada got up from her chair and moved to the table. She let them sit, three together in front of the screen. Frank wrote the letters down on a piece of paper and went to his office. Hayato sat where he was, gazing at the screen. Charles-Robert got a pad of lab stationery and scratched away at it for a while.
Half an hour went by. Ada worked, too, at a piece of paper, on which she wrote the string of letters from memory.
Hayato was the first to speak. “Is it possible,” he said, hesitantly, “that he was already . . . experiencing symptoms? When he made this?”
“It’s possible,” Ada admitted. She was hovering on the verge of disappointment. She had hoped, she realized, that she would be leaving the lab that day with an answer.
“I’m not saying it’s not solvable,” said Hayato. “But on first glance it looks incredibly difficult. The fact that it’s so short, for one thing, means that patterns will be difficult to discern. We can probably create a program that might give it a go. But I think there’s a distinct possibility that this was made with the equivalent of a one-time pad,” he said. “Which means that a program won’t be able to solve it. Not this century, anyway.”
“Okay,” said Ada quietly. She looked back and forth from Frank to Charles-Robert. But they looked similarly confounded. “Okay,” she said again. “Don’t worry about it.”
“Did he give you anything that could have functioned as a one-time pad?” asked Charles-Robert. “A different string of numbers or letters?”
“I don’t think so,” said Ada. She felt despair coming over her. The truth was that David had given her any number of such things: he had constantly given her codes and puzzles, little bits of tangled language that, formerly, it had been her great joy to figure out. Any one of them, she thought, might be the one-time pad that would solve David’s last puzzle.
“We’ll all keep working on it,” said Hayato.
“Are you sure we can’t tell Liston?” said Frank. “She’s good at this stuff.”
“Not yet,” said Ada quickly. She tried to think of an explanation she could offer, but she came up with none. She was angry: that was all. She couldn’t tell them this. “I’ll tell her soon,” she added.
She realized, as she was leaving, that she did not want to leave. She breathed in, deeply, before she walked through the door; and had a sharp and sudden memory of the last time she left, the night of the retirement party. Only that time, it had been with David. And that time, David had still been himself.
To Ada’s surprise, when she walked back into the house that evening, Melanie, Janice, and Theresa were standing in the kitchen with Liston and William and some of his friends. The girls were wearing bright, absurd dresses: pinks and yellows and greens, quite different from the muted colors of the Queen of Angels uniform that she saw them in daily. The boys were wearing tight jeans and fat high-top sneakers and oversized white button-downs. Liston had a camera out, a clunky Polaroid that she had had since the sixties, and was flapping a newly printed photograph in front of her face.
“We were wondering where you were!” Liston said to her, and it occurred to Ada suddenly that it was the night of the dance the school called Jamboree. It drew from Catholic high schools all over the city, and it was the first year that her group of friends, as ninth-graders, were eligible to go. The girls at Queen of Angels had been discussing their outfits for weeks.
“I was visiting David,” Ada said, lying, and Liston opened and closed her mouth, as if deciding against a reply.
“Run and get changed,” she said instead. “It’s 8:00 already.”
The teenagers in the room looked at her blankly. Ada had the uneasy feeling that they had been relieved she wasn’t home; that they had been hoping to make an escape before she walked in. She had not been spending much time with them in recent weeks; her trips to the library with Gregory had occupied her afternoons and weekends.