"The way I did," Aldous corrected. "There are some people who don't deserve to live, my friend. I learned that lesson too late. It cost me my wife. I won't make that mistake again."

2.

"G.o.dd.a.m.nit!" Craig shouted as he sprang to his feet and stepped off the Planck platform and onto the gravel rooftop, storming furiously, but aimlessly away. "G.o.dd.a.m.n it to h.e.l.l!"

"I'm sorry for your loss," the A.I. began, "but we have-"

"You have no idea what you're saying you're sorry for!" Craig shouted. "You have no G.o.dd.a.m.n idea what I've lost! You're a machine! G.o.dd.a.m.nit! I'm in h.e.l.l! Get me out of this h.e.l.l!"

"Craig," the A.I. replied calmly, "your MTF generator is back online, and we need to find a more secure location immediately. Brace yourself."

Instantly, Craig was encapsulated in his green coc.o.o.n once again, as the A.I. took over the flight systems and quickly scooped him into the air, then flew him down into an alley shaded from the brilliant morning sunshine and toward a giant, abandoned warehouse. Pillars of light shone down through the broken slats of tile in the roof like the fingers of G.o.d, illuminating the h.e.l.lish, dark interior. The A.I. set Craig down on the top floor of the sprawling building, and his boots sank into the two inches of dust that covered the ground.

"Be careful," the A.I. warned. "The floor is not entirely structurally sound. There are holes."

"Where are we?"

"This is an abandoned textile-"

"No!" Craig shouted with frustration as he used a powerful blast of energy to rip apart his cuffs, tearing through them like b.u.t.ter. "Where are we? What universe is this?"

"332."

"You know that's not what I'm asking," Craig spat back as he clasped his hands over his head. He resisted the urge to start pounding on his own skull. He wanted to dig his fingers inside and pull the A.I. out.

"I'm afraid that physically damaging your own brain will do little to alleviate your anger, Craig. However," the A.I. continued as his form suddenly appeared only two meters away, "if you wish, you're more than welcome to pummel me in this form."

"What is this?" Craig asked with a snarl.

"A hallucination."

"What do you mean?" Craig demanded. "You mean...I'm imagining you?"

"No, I am quite real, but I'm accessing the region of your brain that is responsible for hallucinations. It is a major component of the mind's eye technology. The hallucination is visual, auditory, and also tangible, so if you punch me, your brain will make you feel as though your fist has made contact with my jaw."

"That sounds tempting," Craig replied, nodding enthusiastically at the thought.

"I'm ready when you are," the A.I. said in his typical matter-of-fact tone. He closed his eyes and tilted his jaw so Craig could hit him at an angle that would level the most force and, in theory, produce the most satisfaction.

Craig wound up, but after a couple hesitations, he abandoned the effort.

"Are you sure, Craig? Your system is rife with enormous amounts of cortisol and adrenaline. This would likely help you alleviate some of it and I would not feel any discomfort."

"That's the problem," Craig replied. "I want somebody to feel some discomfort."

"Your anger is understandable."

"Where are we?" Craig repeated his question.

"I'm sorry, Craig, but I do not feel comfortable relaying that information to you."

"Why?"

"Because you will undoubtedly choose to interfere with this timeline, just as you did in the last."

"And that's bad, why? Don't tell me you're siding with the Purists."

"Regardless of the possible implications for the history of this universe and the multiverse at large, the greater concern is that the Purists will expect you to interfere-and they'll be waiting."

"Hold on," Craig responded, as something in the A.I.'s explanation did not resonate with him. "How can the Purists be here? I thought we just abandoned them in the last universe."

"We did. However, we have to a.s.sume they will locate your Planck platform and follow us here."

Craig began shaking his head as he paced away.

"Be careful," the A.I. warned once again.

"I want an explanation. What the h.e.l.l is going on? How are we hopping from one universe to another?"

"Certainly. As I said earlier, explanations are my forte. We are using the Planck platform to concentrate enormous amounts of energy at one point, thereby manipulating Planck energy and causing s.p.a.ce and time to become unstable. In the midst of that forced instability, a bubble forms. The bubble acts as a gateway to a parallel universe."

"A bubble?"

"It lasts only for a microsecond, which is why you don't see it and why, to you, it appears as though you have instantly traveled to another universe."

"So, you're saying you discovered parallel universes?"

"In tandem with the researchers at our facility, yes."

"But...but how can parallel universes exist?"

"They've been incorporated into membrane theory for decades, Craig. However, once humanity attained access to an artificial intelligence with sufficient power not only to process the enormous amounts of data already available, but also to creatively concoct experiments at a rate that humans simply couldn't match before, it was only a matter of time before evidence was uncovered. The universe, Craig, is really a multiverse, floating in an infinite darkness known as the bulk, and is only one of an infinite number of parallel universes."

"Impossible," Craig replied, mesmerized.

The A.I.'s eyebrow arched quizzically. "The evidence is all around you."

"I know. I know, but...d.a.m.n." Craig sat on the dusty floor and rested his elbows on his knees. "I just...I've never felt so...lost."

"You would prefer to believe that our universe exists alone?"

Craig shook his head. "I don't know. I just wish I wasn't here. I wish I was with Sam and none of this had happened."

"In many universes, that is indeed the case."

Craig shot the A.I. a glare. "That's not much solace."

"Perhaps not, but it is true, however. The many worlds theory has turned out to be more than just a theory. Indeed, all possible alternative histories and futures are real, each one encapsulated in its own universe. The universes branch off from one another. If you could see the bulk," the A.I. continued as he conjured a 3D computer image of what he described, "it would look very much like the neurons in your brain, each universe splitting off the last, connected, yet separate. The 3,000 parallel universes, or exo-universes, that we have currently identified are those closest to us within the bulk."

"Okay. Crazy as that sounds, it kind of makes sense. And what about these magnetic fields we've been generating? I didn't know magnetic fields could do these things. Why didn't we have these before?"

"The magnetic fields of the past were quite simple in comparison to what you are generating with your MTF. This is the age of nano materials, Craig. Your magnetic field is the result of electromagnetically energized particles that are organized into patterns that make them spin at high velocities." Once again, the A.I. projected a helpful animated 3D image to ill.u.s.trate his point. "If we had a microscope powerful enough to see these materials, we'd see that the pattern they form is similar to a honeycomb structure, with the north and south poles reacting to one another in such away that the attractions and repulsions cause them to spin. The honeycomb structure is woven into a net that surrounds you. This not only forms your protective coc.o.o.n, but it can also propel you in whichever direction you desire by propelling particles away at high velocities."

"And these fields are strong enough to protect us when we go through the Planck?"

"Yes. The Planck platform generates a super-strong field in the same instant in which the Planck bubble forms. It is a.n.a.logous to a firewall, protecting you from the instability of s.p.a.ce and time that surrounds you."

"All right. I get it."

"Indeed. Although it isn't possible for any human to fully understand the enormous calculation and experimentation required, the general concepts are relatively easy to grasp. And, speaking of relativity, Aldous asked me to explain to you why the universes are moving at different time rates."

"Yeah, I don't need to know if it's going to be too complicated," Craig said, holding one hand to his forehead while he waved the A.I. away with the other.

Undeterred, the A.I. continued. "It's quite simple. Each universe is actually moving at the same time rate. Therefore, they are obeying Einsteinian principles. However, time moves differently according to ma.s.s and gravity, so while the universes might be moving at the same rate in totality, the speed of time in the vicinity of the Earth can be dramatically different."

"I didn't quite catch that," Craig replied after giving his head a quick shake. "One more time."

"If, for instance, a few galaxies begin moving toward the Milky Way, converging upon it slowly like clouds that do not appear to move from a great distance but are actually traveling quite rapidly, then time in the Milky Way can slow dramatically because of the extra ma.s.s and gravity exerted upon it. If, however, galaxies trend away from the Milky Way, the reduced ma.s.s and gravity pressure causes time to move more quickly. This is why the multiple Earths can differ so greatly in their time periods. Overall, however, when averaged for the entire universe, time is a constant."

"I think I understand now-a bit TMI, but okay. So what year are we in in this universe?"

"Again, Craig, it would be unwise-"

"You said you respect my free will."

"I do. However-"

"Good enough," Craig said as he lifted off, the A.I.'s holographic image disappearing and then reappearing in Craig's mind's eye as Craig flew through the largest of the holes in the ceiling and straight up over the building, trying to get above the tallest of the surrounding buildings to attain the best vantage point. It was only a matter of seconds before a colossal manmade structure appeared to the south, backdropped by a perfect blue morning. "Oh my G.o.d," Craig whispered as he gazed at the Twin Towers.

"It's September 11," the A.I. finally conceded. "2001."

3.

Craig didn't hesitate to ignite his coc.o.o.n and blast off as fast as he could toward the towers. "What time is it? How long do we have?"

"Craig, you have to stop," the A.I. replied.

"What time is it, d.a.m.nit!" Craig demanded.

Without warning, Craig's forward momentum dropped dramatically, as though he were trying to make his way through thick mola.s.ses. "What are you doing? Stop it!" he shouted as he began to pull back from his intended destination.

"I'm sorry, but I cannot allow you-"

"So you're a liar!" Craig shouted. "Free will? Bull!"

"I would never lie to you, Craig. However, you have not afforded me an opportunity to explain."

"I'm tired of your attempts to justify-"

"My protestations are not only metaphysical, Craig. They are also practical. If you approach the Twin Towers, you will likely be apprehended and perhaps even killed immediately. The Purists may be waiting for you there, expecting you to make your move."

"How?" Craig asked as he floated high above the city streets. "We just left them on the t.i.tanic a few minutes ago. They had to find the Planck platform and sink the ship, and that would take-"

"Time, as you understand it, is irrelevant in this instance. The Planck platform creates an instability in s.p.a.ce time that is chaotic and difficult to predict. The distortions are very much like water. Depending on where one catches the time wave, the discrepancy can be several minutes. It is not even impossible that the Purists actually arrived in this universe before we did."

Craig's eyes narrowed as he stared toward the towers, a grimace forming on his lips. "That sucks, but it's not enough to make me give up. We still have to try."

"I shall help you," the A.I. replied, "but you must listen to my plan."

"I'm all ears."

"While trying to intercept the airplanes at the tower would be a fool's errand, virtually guaranteeing that the Purists would be able to stop you at their leisure, there is another way."

Craig immediately understood. "The airport! Do we still have time?"

"It is currently 7:31 a.m. Lead hijacker, Mohamed Atta will be boarding American Airlines Flight 11 at 7:35 a.m. at Boston's Logan International Airport. I can get us there if you allow me to take over your flight systems."

"You've already done that."

"Yes. However, I won't go anywhere without your permission," the A.I. replied.

"Fine! You have my permission! Let's go!"

Without a word, the A.I. turned Craig around to face north and blasted off. In just seconds, they had accelerated to a speed Craig had never experienced before.

"Holy...this is fast."

"Logan is 310 kilometers away, so to make it in time, we have to travel nearly 6,000 kilometers per hour."

"Will we make it?"

"a.s.suredly. However, we will not be able to stop the coordinated attacks. I will patch you through to the security at Logan, and you can have them relay the information and stop all four flights from taking off."

"What am I supposed to tell them? 'I'm a guy from the future with a robot in my head. A bunch of terrorists are going to fly planes into the Twin Towers. Please have Airport Security detain them.' I don't think they'd buy it. I'll find myself in a straightjacket before breakfast!"

"Tell them the truth. You're former U.S. Air Force Special Forces."