But Bishop wanted more. He had never been happy in his own time, and before leaving it behind, he had written on his biotime capsule, “My true friend died before I was bom and my perfect lover will be born after I die.”

And he told the historians, “Translate that to this: if you want perfection in an off-the-rack world, you will be disappointed, because the odds are that in the whole span of history, your lifetime is too small to expect to meet the perfect love. Of course, you can cheat that by biotiming.”

As it happened, he met his perfect love after the very first “timejump,” among the Ceres-bound colonists; and he had abandoned the biotimers to help her build a new world. For six brief years he had known perfect happiness, and then it was all snatched away from him forever by Ceres’s one and only construction accident. That was eight years ago; and though the option had always remained open to him, he never rejoined Project Biotime. He had spent most of the past eight years living with machines instead of people, indifferent to the future, until now, when it was all so clearly too late.

By the time the maglev had shuttled him from Isak’s home to the north pole, a pressurized tent had already sealed off his stricken, half-eaten robot from the rest of Ceres, a phone line had already connected the tent to the colony, and a system of laboratory modules was already being trucked to the site.

The tent itself enclosed a fully equipped “clean room.” Bishop had entered through an airtight glove box that fit him like a space suit, and in the center of the room one of the robots was melting in the warming air. It occurred to him then—too late—that no one should have been allowed to pressurize the chamber or heat the air. A second robot had stood on the far side of the room, ready to assist him. Now both machines lay in melting heaps, and Bishop found himself alone and afraid, abandoned by his crew, as he retreated to a module whose hull was twisting out of shape and leaking air. He tightened his suit helmet, hoping to buy himself a few more minutes of life, and began his final report to Isak.

There was very little he could say that was new to the president. One of the machines had been tricked into producing a substance that, for lack of a better name, Bishop had come to call a “molecular virus” or “template”—with which it had promptly infected itself.

Isak had replayed the images over and over on his pad: Bishop’s robot on the floor of the tent, being eaten as if by a mighty cancer, breaking open like a poorly constructed beehive, thousands of microrobots spilling out of the rent across its abdomen, writhing and melting; Bishop’s robot assistant placing samples under the scopes; and then, after an hour or two, the scopes themselves seizing up and flaking apart… and then the robot assistant.