Quinn went on. “Amanda called some of her father’s friends still at the department. None of them could make sense of this, either.”

“They couldn’t, unless they knew how Greg set up the code.”

“Do you?” It burst from her, again against her vow to remain completely silent while he was here. But this was too important.

“Yes.” He stopped.

“Don’t play games, Adam Kirk,” she snapped. “This file was last saved the day he died. It could be important.”

He finally looked at her then. And she saw the shadows that darkened his eyes. Shadows that were familiar, for she’d seen them often enough in the mirror. She saw the muscles in his jaw tighten, then release. Then he looked back at Quinn.

“It’s a double alphabet code.”

Quinn glanced at the screen. “What about the numbers?” he asked, obviously knowing what Adam had meant by that.

“They were to work with his foundation alphabet, because it had repeating letters.”

“So he numbered them,” Quinn said in understanding. “A one through five, N one through five, and so on.”

Adam nodded.

“Could someone please explain to the non-secret agent in the room?” Amanda said, trying to keep her frustration out of her voice. She knew she was touchy about this, and Adam should get some credit for at least coming when he was asked. Shouldn’t he?

Quinn answered her. “Double alphabet. One, the real one. The second, the encoding one, can be anything. The simplest—and oldest—is the real one in reverse order, but you can use anything as long as you have twenty-six letters.”

“But how does it work?” Hayley asked, and Amanda threw her a grateful glance, glad she wasn’t the only one lost.

“You just write out the two, then substitute the encoding alphabet letters—or in this case also some numbered letters—for the real alphabet,” Quinn explained.

“Or if you’re like Greg,” Adam said with a sad smile, “you do it from memory. I swear, he could read his encoded stuff like it was straight English.”

Amanda’s breath caught. It had always amazed her, her father’s memory. Brain’s a steel trap for trivia, Mandy, he had always warned her when they had watched a quiz show on television when she was a kid. Somehow that Adam knew that unsettled her. As if he had shared something personal she had thought of as her own. Childish, but sometimes she just slipped back into being a girl who really missed her dad.

“But we’re still at the starting block without his encoding alphabet,” Quinn said.

Adam sucked in a deep breath Amanda could hear. Then he let it out slowly. “I know that, too.”

Amanda stared at him. And suddenly another memory, one pushed out of her mind long ago, crashed back. He’s a good man. I trust him completely.