“But why, Paul? What does he think he’s doing?”

It was a question for which Jan did not expect an answer; perhaps it would never have an answer. Their scooter, still descending, was racing along through the outermost layers of the atmosphere. A whistle of air sounded on the hull. Behind them, the view across the horizon revealed a tiny flicker of red, dropping into the towering mass of a thunderhead. Jan, forgetting their own situation, could not take her eyes off that point of light.

It fell and fell and fell; and then, suddenly, the Mayfly’s beacon signal was gone.

Jan caught her breath and closed her eyes. When she opened them again the control displays showed that the Fly-boy scooter was dangerously low. Drag on the ship was hindering the effectiveness of the engines in pulling them out of their descent.

“Paul.” She reached out, then had enough sense not to touch him. He had curled his body into its most comfortable position. “Paul, if we don’t make it I just want you to know. You couldn’t save Sebastian, but you saved me in all kinds of ways.”

“We’ll make it.” He was studying the control panel and the horizon ahead. “We’re holding our own in altitude. But I didn’t save you. You saved yourself.”

Jan felt warm all over. She pushed what she wanted to say into the back of her mind. It would keep. Instead she said, “If we’re going to make it, you need help. Tell me how to place a call for a medical vessel.”

As she followed his directions for an emergency call she saw that he was right. The scooter was slowly lifting away from Jupiter.’ She and Paul had begun a long journey, all the way around the body of the planet on a high swingby that would at last take them back toward Ganymede.

And then there would be a longer journey, one that three months ago she could not have imagined: a life without Sebastian. He was gone, gone forever. Life went on.

33

The last conversation that Alex remembered was short and simple.

As Janeed Jannex and Paul Marr rushed out, he said to Milly Wu, “What now?”

She shrugged. “We do what Bat said. We wait for him to show up.”

Alex wandered out into Sebastian Birch’s living room and flopped down on an easy chair. Perhaps it was sheer physical fatigue and lack of sleep, but he was filled with a sense of failure. He had been asked by Bat, with that strange urgency in his voice, to find and guard Sebastian Birch. It was not Alex’s fault that Birch had vanished, yet it felt like his fault.

Milly Wu sat down in a chair opposite. She shook her head but did not speak. Alex closed his tired eyes and tried to relax.

After what seemed like no more than a few minutes, someone gripped his upper arm. He looked up, expecting to see Milly. Magrit Knudsen was standing over him. Confused and still dopey with fatigue, he sat upright and stared around him. Milly Wu had vanished.

“Where the devil did you spring from?”

It was no way to talk to a superior cabinet officer three levels and more above you, but Magrit Knudsen didn’t react. “Bat called me,” she said. “You know, when that man stopped working for me I thought there would be no more midnight crises and alarms. I should have known better. How did he drag you in? Don’t bother to answer that. Are you awake?”

“Yes.” The rush of adrenaline after he recognized Magrit Knudsen made his statement true.

“Then come on. He wants you there for what may be the finish. We have to go up a level. That’s where the others are.”

Alex rose to his feet and followed her, out of the apartment and up a flight of stairs. She led him into what was clearly some kind of facility control center. The room was dominated by a three-dimensional display as big as any that Alex had ever seen. It showed an image of a section of Jupiter’s clouded outer layers under extreme magnification. Alex could make out individual pixels in the vortices and cloud banks.

Bat was seated on the floor, immobile and staring at the display. On his left, doll-sized compared with his bulk, sat Milly Wu. Behind Bat, hovering nervously over him with hands clasped together like a praying mantis, stood Ligon’s chief scientist, Bengt Suomi.

Magrit Knudsen walked forward and said, “Any success?”

Bat did not move or speak. It was Suomi who answered, “Just the opposite, I’m afraid. We had close contact until a couple of minutes ago. Then something happened between the ships, and now they are diverging.”

Alex walked forward to stand next to Milly Wu. Now he could see in the display what the others were staring at so intently: two bright points of light stood out against the face of Jupiter. As he watched, they moved infinitesimally farther apart.

Milly Wu glanced at Alex and said softly, “Birch’s ship is on the right. Janeed Jannex and Paul Marr have been chasing him. They spent hours in close contact, but now they’re separating. Looks as if they’ve lost him.”

Hours? Alex wondered how long he had been asleep and out of things. Bengt Suomi said suddenly, and with a tremor in his voice, “Range-rate data show that Birch’s ship is still descending. He’s going down, all the way — there’s no possibility he can pull out of it now. The scooter still has a chance. Its tangential velocity component may take it clear of Jupiter. Even so—”

“Even so,” Bat said, “the people in the scooter will die. Sebastian Birch will die. And very soon we will all die.”

We will all die. Alex felt the shiver of a second adrenaline rush through his whole body. What was Bat talking about? The man’s reputation was for understatement, not wild exaggeration. Sebastian Birch was surely going to die — his craft continued to plummet straight downward. Janeed Jannex and Paul Marr’s ship might not be able to alter course in time to escape. But all die? — including Bat? Including Alex himself?

Alex glanced from face to face. He said, “I don’t understand.” He was ignored. Bengt Suomi’s dark-browed glare, Bat’s stoic gaze, Milly Wu and Magrit Knudsen’s wide-eyed stares; they told him nothing. He turned back to the display, just in time to see the speck of light representing Sebastian Birch’s ship wink out and vanish.

Bat said, “Birch is dead. His ship and signal relay have burned up in Jupiter’s atmosphere. I bid you all farewell. We begin to die — now.”

Alex’s chest tightened. The whole room seemed to move into a state of suspended animation as everyone took in a deep breath and held it. The moment lengthened. It became seconds — half a minute — a whole minute.

Finally, Bengt Suomi gave the high-pitched, tittering laugh of a man who never laughed. Bat exhaled hugely and said, “Except that we are not dead. We are not dying. We are alive, and I was terribly wrong. I built a city of speculation upon a shallow bank of improbability, which now has crumbled and collapsed. I offer my sincere apologies.”

“Apologies? Apologies that we are alive?” Suomi gave a nervous shuffle, like a little dance. “No, I’m the one who was wrong. Some mistake in my group’s experiments, something in our data. According to our calculations, the catalytic reaction and phase change should have begun instantaneously. The estimated expansion rate was many kilometers a second. We should have observed visible effects as soon as Birch’s ship lost hull integrity. We must repeat the work at once and find out where we were in error.”

Alex burst out, “What the hell is this all about? Dead, not dead. Who were you talking about? It doesn’t make sense.”

Magrit Knudsen added, “Really, Bat. You’ve outdone yourself. You warn of the coming apocalypse, you drag us out of bed — and all for nothing.”

Bat ignored both of them. “Yes,” he said, speaking only to Bengt Suomi. “The work must be repeated. Tonight.” He glanced at a readout beside the big display. “Or, to be more accurate, this morning. We must pursue and discover the flaw in our logic. As soon as we have an explanation, I promise that everyone here will share it.”