"Do you want me to let it in?" asked Don, still looking at the picture of the round, blue face, with its unblinking eyes.

"Um, sure," Sarah said. "I guess."

She watched as he made his way to the little staircase leading to the entryway, and began the slow pilgrimage down, one painful step at a time. She followed him and stood at the top of the stairs — and noted that one of her grandkids had forgotten a colorful scarf here. By the time Don reached the door, the bell had sounded a third time, which was the maximum number it was programmed to allow. He undid the deadbolt and the chain, and swung the heavy oak door inward, revealing—

It had been weeks since Sarah had seen one in the flesh — not that "in the flesh" was the right phrase.

Standing before them, gleaming in the sunlight, was a robot, one of the very latest models, she guessed; it looked more sophisticated and sleeker than any she’d seen before.

"Hello," the robot said to Don, in a perfectly normal male voice. It was about five-foot-six: tall enough to function well in the world, but not so tall as to be intimidating. "Is Dr. Sarah Halifax in?"

"I’m Sarah Halifax," she said. The robot’s head swiveled to look up at her. Sarah suspected it was analyzing both her face and her voice to make sure it was really her.

"Hello, Dr. Halifax," the robot said. "You haven’t been answering your household phone, so I’ve brought you a replacement. Someone would like to talk to you." The robot raised its right hand, and in it Sarah could just make out a clamshell datacom.

"And who might that be?" she asked.

The robot tilted its head slightly, giving the impression that it was listening to someone somewhere else. "Cody McGavin," it said. Sarah felt her heart skip a beat; she wished she’d actually been on the staircase, instead of just above it, so she could have grabbed the banister for support. "Will you take his call?"

Don turned to look at Sarah, his eyes wide, jaw hanging slack.

"Yes," she said.

The word had come out very softly, but the robot apparently had no trouble hearing her. "May I?" it asked.

Don nodded and stepped aside. The robot came into the entryway, and, to Sarah’s astonishment, she saw it was wearing simple galoshes, which, in a fluid motion, it bent over and removed, exposing blue metal feet. The machine walked across the vestibule, its heels clicking against the old, much-scuffed hardwood there, and it easily went up the first two steps, which was as far as it had to go to be able to proffer the datacom to Sarah. She took it.

"Flip it open," the robot said helpfully.

She did so, then heard a ringing through the small speaker. She quickly brought the device to her ear.

"Hello, Dr. Halifax," said a crisp female voice. It was a little hard for Sarah to make out; she wished she knew how to adjust the volume. "Please hold for Mr. McGavin."

Sarah looked at her husband. She’d repeatedly told him how much she hated people who made her wait like this. It was almost always some self-important jackass who felt his time was more valuable than anyone else’s. But in this case, Sarah supposed, that was actually true. Oh, there might be a few people on Earth who made more per hour than Cody McGavin, but, offhand, she couldn’t name any of them.

As Sarah often said, SETI is the Blanche Dubois of scientific undertakings: it has always depended on the kindness of strangers. Whether it was Microsoft co-founder Paul Allen donating 13.5 million dollars in 2004 to fund an array of radio telescopes, or the hundreds of thousands of private computer users who gave up their spare processing cycles to the SETI@home project, the Search for Extraterrestrial Intelligence had managed to struggle on decade after decade through the largesse of those who believed, first, that we might not be alone, and, later, that it actually mattered that we were not alone.

Cody McGavin had made billions by the time he was forty, developing robotic technology. His proprioceptive sensor webs were behind every sophisticated robot on the planet. Born in 1985, he’d been fascinated by astronomy, science fiction, and space travel all his life. His collection of artifacts from the Apollo program, an endeavor that had come and gone long before he was born, was the largest in the world. And, after the passing of Paul Allen, he’d become by far SETI’s biggest single benefactor.

As soon as Sarah had been put on hold, music started playing. She recognized it as Bach — and got the joke; she was probably one of the few people left alive who would. Years ago, long before the first Draconis signal had been received, during a discussion of what message should be beamed to the stars, Carl Sagan had vetoed the suggestion of Bach, because, he’d said, "That would be bragging."

In the middle of the concerto, the famous voice came on; McGavin spoke with one of those Boston accents that managed to say "Harvard" with no discernible R sound. "Hello, Dr. Halifax. Sorry to keep you waiting."

She found her voice cracking in a way that had nothing to do with age. "That’s all right."

"Well, they did it, didn’t they?" he said, with relish. "They replied."

"It seems so, sir." There weren’t many people an eighty-seven-year-old felt inclined to call "sir," but it had come spontaneously to her lips.

"I knew they would," said McGavin. "I just knew it. We’ve got us a dialogue going here."

She smiled. "And now it’s our turn to reply again — once we figure out how to decrypt the message." Don had been moving across the little entryway, and now was climbing the six stairs. When he was all the way up, she held the datacom at an angle to her face so he could hear McGavin, too. The robot, meanwhile, had taken up a position just inside the front door.

"Exactly, exactly," said McGavin. "We’ve got to keep the conversation going. And that’s what I’m calling about, Sarah — you don’t mind if I call you Sarah, do you?"

She actually quite liked it when younger people called her by her first name; it made her feel more alive. "Not at all."

"Sarah, I’ve got a — call it a proposition for you."

Sarah couldn’t help herself. "My husband is standing right here."

McGavin chuckled. "A proposal, then."

"Still here," said Don.

"Hee hee," said McGavin. "Let’s call it an offer, then. An offer I don’t think you’ll want to refuse."

Don used to do a good Brando in his youth. He puffed out his cheeks, frowned, and moved his head as if shaking jowls, but said nothing. Sarah laughed silently and swatted his arm affectionately. "Yes?" she said, into the datacom.

"I’d like to discuss it with you face-to-face. You’re in Toronto, right?"

"Yes."

"Would you mind coming down here, to Cambridge? I’d have one of my planes bring you down."

"I… I wouldn’t want to travel without my husband."

"Of course not; of course not. This affects him, too, in a way. Won’t you both come down?"

"Um, ah, give us a moment to discuss it."

"Of course," said McGavin.

She covered the mike and looked at Don with raised eyebrows.

"Back in high school," he said, "we had to make a list of twenty things we wanted to do before we die. I came across mine a while ago. One of the ones I haven’t checked off yet is ‘Take a ride in a private jet.’ "

"All right," she said, into the datacom. "Sure. Why not?"

"Terrific, terrific," said McGavin. "We’ll have a limo pick you up and take you to Trudeau in the morning, if that’s okay."

Trudeau was in Montreal; the Toronto airport was Pearson — but Sarah knew what he meant. "Fine, yes."

"Wonderful. I’ll have my assistant come on, and he’ll look after all the details. We’ll see you in time for lunch tomorrow."

And the Bach started up again.