Alpha Centauri system, 1.0 A.U. "north" of the north magnetic pole of the primary star

"Attention on deck," a voice called out. Dozens of officers and senior non-commissioned officers chiefs came to their feet. Their leader entered the room from the side and walked to the podium. His aides had already arranged for the podium, the tables and chairs, the sound system, and even the dinner which their guests would be served in about an hour. It would be one of the last meals they would ever taste from Earth-grown foods.

"At ease; be seated," the Commander-in-Chief, Fleet Admiral Ungele M'boto, said. He was a bearded, old African man, short with a thick South African accent. His tired eyes scanned the room, letting his silence draw their attention even further.

"Ladies and gentlemen, welcome to Alpha Centauri. I've called you all here to discuss our situation. Food, water, heat, medicine, sanitation. All of these are in short supply; we're going to have some trouble. Power, fortunately, appears not to be a problem, but we don't have replicators." A few chuckles came from the audience. "We're going to be heading for the nearest known Earthlike planets; hopefully we'll find some source of edibles out there."

"Earth is closed to us. Let me repeat that. Earth is closed to us. We will go back to Earth, but not today. As a result, the next few weeks are going to be very difficult. After this meeting, I want all of you to meet with Ms. Peters -- stand up please... thank you -- and tell her what you can do to help. Most of you have skills in the basics of survival; we need you to teach the other refugees and coordinate with them. Most of them are not military and never can be; remember that when you're training them."

"If we all pitch in, we will make it. It's never been done before, not in space, but it will be done. Failure will never be an option." Mboto's voice was resolute; he pounded the podium once, softly.

"Next, we have evidence and a couple FBI experts on board who were in China. I want a full report of what they knew. The President ordered our departure based on partial information, the rest of which we probably have on board. I want it, in forty eight hours -- after we've taken care of our immediate needs."

"Gentlemen, our watches are set to Greenwich Mean Time, without the daylight savings. That will remain indefinitely. More on that in a moment. The time now is eight hundred hours; we will reconvene here at this time tomorrow."

"Now, immediate issues being taken care of, there's something which until now, only myself, Ms. Peters, and Vice Admiral Philemon were cleared to know. As we are in immediate danger and there's not much we can do about it, we have decided you have a need to know this. I do not want this to become common knowledge yet; what I say here stays in this room."

M'boto waited to observe for any protests, any signs that he was not understood. The faces were determined, grim, but clear.

The large viewscreen behind the Fleet Admiral lit up with radar pictures of Hercules leaving Earth's local space. "Twenty-four hours and two minutes ago, we departed Earth. However, no one on Earth knew we could go faster than lightspeed. You all have our engineers -- and our navigators -- to thank for maintaining that secrecy. I won't bore you with the details of how we did it, except to say we can now treat time as a dimension which we can maneuver through. That is why we are all here today. We have the ability to travel through space and time with no limits on either of them. But should we?"

The confused looks on his officers' faces showed that whatever they had been expecting, it wasn't this. "As you know," the Admiral went on, "our own science fiction -- some of it less fiction than fact, now -- has long wrestled with the concepts of time travel and the theoretical dangers it poses. Those dangers are no longer theoretical; they are now practical. We now have the ability to intervene directly in our own planet's history." The murmurings and whisperings began.

"I've been reading up on time-travel theories and stories for the last few weeks. The single most-quoted story involves a grandfather paradox: namely, if you kill your own grandfather before he ever meets your grandmother, do you exist? If you don't, then does your grandfather die? It is a troubling question, one that without experimentation on a safer subject cannot be answered. One that Earth philosophers and scientists advise is too dangerous to risk asking, for fear of an answer which we may not survive."

"However, we have signs showing the question has already been asked... and answered." The murmurings and whispering stopped abruptly. He knelt down

The Admiral clicked a button, and the next slide came up. It showed a horizontal tree diagram, most of the branches (and the trunk) in green dashes. Some of the dashed branches branched off solid green branches. The solid green branches invariably branched off a single parent solid green branches, and only one solid green branch came off of the trunk -- where to the left of that branch, the trunk itself was a solid green, and to the right, it was dashed. "What you see here is a 'snapshot' of the history of time about four hours ago. The dashed branches represent timelines that no longer exist. The solid branch indicates our timeline, which does exist."

There were also light blue arcs reaching between points in the tree, like spiderwebs. All of them ended at a branch point, and possibly at both branch points. "The arcs you see represent transitions in time: time travel. In some cases, the changes these time travelers have wrought have been small. In others, quite large, to where the timeline that started the change had no great resemblance to the one the change created." He let that float in the air for several seconds.

"We have only recently begun scanning the timeline to catalog these change events. But it should be noted that every single change event is associated wth a new timeline. If you go back in time and change history, you may not recognize anything from your own time." He let that float as well. Then he dropped the bombshell.

"Or worse, if the situation demands you change history, you might recognize a great deal from your own time, after the change."

"I can attest to that," a woman's voice interrupted from the back. The crowd stirred, wondering who would dare speak without the Admiral's permission.

Especially who would dare to do that and not wear a uniform. Physically speaking, she was unremarkable, a plump woman in her early thirties, already walking down the steps towards the podium. Within seconds, security guards had started moving surreptitiously towards both the woman and the platform.

"I am Skietra," she said. "And before you ask how I got here, I'll tell you I'm not human. Nor am I Velorian or Arion. Actually, I'm older than all of them combined. I created them."

A loud, angry gasp from the crowd.

"I created you too," she answered immediately. By then the guards had trained weapons on her. She looked at them nonchalantly. "Oh, please, put that away before I do," she said, annoyed. "It's just a waste of your time. I'm not here to hurt you."

The Admiral's eyes narrowed. He'd lost his father and two daughters to in the war they were running away from. And this thing could be to blame. He deliberately did not give the order for the security to stand down.

Skietra looked at him directly. "Suit yourself," she said as he thought this. The weapons disappeared, hands tightened on air. She continued on to the front of the room, guards shocked behind her. One of them recovered quickly and charged her, but his superior officer held his hand up to warn the man off. If she can do that to several EM rifles at once, what can she do to us? Skietra looked at that officer as well, who was behind her. "Good choice," was all she said.

"Those time change events you're referring to?" She pointed up at the viewscreen. "They were real. They happened. And whole timelines have vanished as a result. I know, because I saw a lot of them." She turned around and addressed the crowd directly. "In fact, most of them are a direct result of Homo-class species such as your own."

"In another timeline, about 1300 years in your past, I created a species based on Homo Sapiens, projecting where their natural evolution would take them. I added in a few features, such as the ability to project laserbeams from eyes. Ah, yes, I see some of you have met O'mara. Well, her laserbeams are much like what you'd find in my creations. If they still existed." She jumped up and floated in midair, her finger tapping one dashed green branch in particular.

"Here," she shouted. "Here is where I created them, on this timeline, in that spacetime. And I put them on a planet my people called Velor. Several hundred years later, they adopted for themselves the species designation, Homo Supremis." The floating woman smiled wryly. "I thought it was kind of arrogant of them, but appropriate." Then she sighed, and moved her hand far to the right, to where a blue arc intercepted a branch springing from that one. "And here is where it all went haywire..." The blue arc sprang upward and moved back almost to where her finger had first touched: a little bit before, to another branch.

"That's on the order of 350,000 years, sir," an aide whispered into the Admiral's ear.

Skietra looked down, smiling. "Yes, almost exactly that. Natural evolution of Homo Sapiens had taken, whereas natural evolution of my Velorians had not progressed nearly as far. As a result, the two combatants were almost equals, each having distinct advantages and disadvantages over the other." Before anyone could ask, So, what happened?, she replied. "They fought a vicious war across several hundred star systems, an entire arm of your Galaxy. Ironically, your descendants were losing. Until they went back in time and fixed the situation..."

The Admiral spoke, hushed. "They eradicated Velor."

Skietra laughed from up there, laughed quietly, ruefully, painfully. "No, they didn't eradicate Velor. They colonized Velor."

"Now, mind you, that set everything in spacetime ablaze. Hundreds of thousands of years of history, heavily influenced by my Supremis, gone! And here you had a warlike culture with nearly the same powers set loose on the Galaxy. The ramifications were... enormous." At that, Skietra bowed her head in mourning. "It's bad enough when you must defend your class project before a panel of teachers who disapprove of how you manage it. It's even worse when your project starts erasing other class projects from existence..." She looked up again. "And, for better or for worse, I'm stuck with you."

Clearly, when she referred to "class projects", she meant entire civilizations, species, of beings by the trillions. And "stuck with you," meant, equally clearly, that most of those civilizations were gone.

"I wasn't about to let the attackers get away with it. I went back to when I first visited Velor, to discover these beings, your children, had been living there for about ten years. It took more than I was willing to give to reduce their culture back to barbarism, and then to build it back up into the Velorian society I had once constructed. Two hundred years..." She shook her head at the waste. "By then, my class had not only graduated, but had given up on their projects, left them to fend for themselves. I was the only one who cared. I was the only one who could be blamed for letting it get out of hand." Eternal sadness reflected in her eyes. "I still haven't finished repairing the damage to spacetime. And now, I may never finish. But, when all was said and done with the repairs to Velorian society, the invaders refought their war against their descendants, and thought they had lost in their invasion. Instead, they won and will never know that they won."

She looked up. Her voice gained a new firmness, a new righteousness.

"You will not attempt time travel to change your current history. I've seen the horrors it can create, the wonders it can erase. Don't even think about affecting Earth's history behind you. I'll destroy you if you do."

Then she relented a little. "I know I've called you a class project. And I also know that, despite myself, I can't blame you for what your kind in other timelines have done. My restriction on time travel only affects Earth up to the point where time travel reaches them naturally. Wouldn't make sense for you to blow yourselves out of the sky, like I did with the dinosaurs. This whole Galaxy, thanks in no small part to your descendants from other timelines, is devoid of intelligent life save Homo Sapiens and its descendants. So are the surrounding Galaxies in your local supercluster. It's a big universe, and there's plenty of room for all of you to expand into and meet people who are like you, but make your version of Supremis, the Velorians and the Arions, look like matchsticks -- and feel like them, too."

"As for the rest of the universe, tread lightly. My people are native to another supercluster of the universe entirely, and we are allied with several other species in governing and protecting the sanctity of spacetime from those that cannot govern and protect it for themselves. One reason I'm still around is that selfsame protection, and our efforts to keep the time wars confined to your Galaxy."

"Oh, and please don't go to the Big Bang. Tourism there is a nightmare..." Then, like the guns she had replaced in the armory, she vanished from them.

The Admiral swallowed...