Then he remembered, finally, something he knew from his childhood. Something he remembered that had been a part of Lazarus Hayerian’s early life. He spent time in an old library—in someone’s house? A grandparent, an uncle? He was very young, but he was fascinated with an old atlas, from the 1950s. It still showed all the components of the British Empire in pink, so that Kenya and Tanganyika were pink, as were Bechuanaland and the Rhodesias and Nyasaland. And South West Africa, which was now Namibia, and Bechuanaland had become Botswana, the Rhodesias were Zambia and Zimbabwe, Nyasaland was Malawi—as he remembered, everything fell right into place.

  In the Professor’s childhood brain, there was an elaborate system of geography. Child-Laz not only knew the names of all the countries in the world, from the Vatican and Monaco to the USSR and Red China and the British Empire, but also he knew their capitals—and their borders in such detail that long before the Soviet Union broke up, he knew the names of every Soviet Socialist Republic and how their borders interlocked, so that he could make sense of the tangle of nearly meaningless boundaries among Afghanistan, Kyrgyzstan, Tajikistan, Kazakhstan, Uzbekistan, China, India, and every other polity caught up in that Gordian knot.

  Why didn’t I already know that I knew this? Why didn’t this surface ever before? Because in the original mind of Lazarus Hayerian, it didn’t have to surface, it was already there, near at hand. His brain readily accessed it because it remembered where all this information was stored when it first laid the data down in his neurons. It knew all the connections.

  But his cloned brain did not lay anything down. When the Prof’s brain state was poked into Zero-Laz’s head, it was carefully located in nearly identical places in the brain. Maybe even absolutely identical places. Except that the connections between neurons were not exactly the same. Child-Laz’s nighttime explorations of geography were not within easy reach in Zero-Laz’s memory.

  Laz had reached it now, though, and he saw—and felt—how the map of the world suddenly came alive for him. Each country was an organism, alive, he could feel the pulse of them, just the way he did when he would send himself to sleep by imagining the conquest of the world, not always by war, but by war when it was necessary. Laz never had any ambition to make these late-night mental games into something real. He didn’t really want to dominate anybody. But he knew every polity, every major city, all the landforms and terrains. He knew the world… from a 1950s atlas.

  Now, having remembered that old atlas, the version of it that Child-Laz had imprinted on his own brain, Laz could find it easily, could access all of that old knowledge. So now when he thought of traveling back in time to Giza, say, he ended up in the desert. A desert that had absolutely no monuments of any kind. No pyramids, no sphinx.

  Because he was no longer on Old Earth. He was in the Safe Place, which had had no human beings before a few decades ago. If he wanted the pyramids, he’d have to go way back, before any separation of the timestreams, back when Old Earth was still in its original orbit and ridiculously overpopulated but the human race was cutting back on its growth rate, at least in some places, when here came Shiva. He had to go back before Shiva.

  Was that what cut the Professor loose in time, so he could never stop moving? Because time travel took him back to a planet that no longer existed?

  In order to leave the message for Zero-Laz and Ivy-Zero, he did not have to go back that far. The Prof said he had been to the last Ice Age, and that was way before Shiva showed up. Maybe the Prof went there first, so that he was on the treadmill practically from the start.

  Laz did not want to be on that treadmill. Maybe if he only went back to when the Zees got their cease-and-desist order…

  But that was only a few years after they’d found the Safe Place and divided the world into eight timestreams, plus a few extras. Could Laz travel back to that time and no farther? A time when all eight of the main timestreams were already populated and up and running, but not when the past would take him to the New Place and certainly not to the Old Place. Nothing that would put him on the treadmill that he couldn’t get off.

  Now his experimental trips took him closer and closer to that line. He was getting much better at finding his target locations—his personal geography was there, it only had to be pulled out of mothballs, so to speak. And within a few weeks, he had a sense of Time that allowed him to go back to the right year, even the right season, and to any designated spot on Earth.

  One remaining problem: Which Earth? All eight of the official timestreams were complete copies of the planet, so whatever spot he targeted, he arrived at—in one of the timestreams. He just couldn’t control which one. Most commonly, it was the timestream he was in when he began his time hop, but sometimes it was one of the others, almost completely at random. This was frustrating, but it didn’t ruin anything. No matter where he started, he would eventually reach the right place and time. Hopefully early, so he could get the lay of the land and the habits in the Zees’ life so he could make sure to be in the right place at the right time. Waiting around for a few days, a few weeks even—he could handle that.

  Waiting around in the same place? Why could he do that, while the Prof couldn’t? What did the Prof do wrong all those years ago that made his time traveling so uninterruptible?

  Laz took notes on the terrain near the Zees’ house—estate, really, when you counted all their land—and found the road where the message had been left, and three possible sites that could fit Zero-Laz’s description of the events.

  Then he went home.

  That was the easy one. He could think of his house, he could think of Ivy there in the house, waiting for him, and he homed in on that and… he was there. Usually in the kitchen, but sometimes in the yard, sometimes in his bedroom, and once in her bedroom. She wasn’t there, so he hadn’t inadvertently pulled a Mumbo trick. But he always ended up somewhere on the property.

  And once he was there, he never, never accidently slid into Time and came unstuck. He knew where he was supposed to be, and he got there. Just went. Directly. No detours. No approximations within ten klicks or three years. He went right home within an hour of when he left—even if he didn’t start his time hop at home. That’s where he always returned.

  At dinner—brought this time by one of Central Times’s best restaurants, of which there were many—Ivy asked him, “Why do you seem so relaxed? Usually when you look in the dictionary under ‘stressed out,’ it’s your picture they have there.”

  “I got back to the right time. Close, anyway, I didn’t have a chance to check a calendar. In the first couple of years in the Safe Place, they didn’t print a lot of calendars, because they figured everybody had the data on their phone.”

  “But you were there,” said Ivy.

  “I found three likely places where the message might need to be.”

  “I can see why you’re relieved.”

  “I stayed for hours, and I felt nothing tugging me off into nebulous Time to get lost. I could have stayed as long as I wanted. But I wanted to get home to you. To now.”

  Ivy smiled. “I wanted you back, too.”

  “Not as much as I—”

  “That’s a fun game sometimes, Laz, but I’m still tense. Because while you’ve been familiarizing yourself with how to move around in Time and space, I’ve been doing exactly nothing.”

  “So you haven’t been studying the maps?”

  “I feel like I’ve actually walked the entire route of the Trans-Siberian Railway and the Orient Express in bedroom slippers.”

  “So weary. Let me rub your sore, sore feet.”

  “Don’t literalize the hyperbolous metaphor, Dim.”

  “You once promised to stop calling me that,” said Laz.

  “I never promised. You just commanded me to stop calling you that.”

  “We remember the event very differently. But let’s set that aside for the moment—”

  “Laz. I promise you now. I will never call you by that undeserved nickname again.”

  Laz was a little startled. He knew Ivy was teasing when she was hurtful to him, that it didn’t mean any lack of love. But this, to make the promise now, and so seriously—was this a turning in their relationship? Could they stop their banter and be unfailingly kind? Can I do that?

  But he had not abandoned their conversation as he thought about Ivy’s new promise to him. “My dear,” he said, “I know why the Prof is on the treadmill, while I’m not, and you won’t be either.”

  “What did he do wrong?”

  “Absolutely nothing,” said Laz. “He simply is wrong.”

  “Insulting to your original, but go on.”

  “When I want to come home, I don’t have to go through some ritual of memory, I just think that I want to be home and zap, here I am. I can’t always control what room I go to, if I’m indoors at all—”

  “I remember that time when you arrived in that freezing rain and you didn’t stop shivering for more than an hour, even though I offered—”

  “Yes, the warm bath was exactly what I needed,” said Laz.

  Ivy smiled. “So I’m glad you only have to think, ‘There’s no place like home,’ and without even clicking your heels, you come back to me.”

  “That’s exactly it,” said Laz. “I come back to you. And when you do this, you’ll come back to me. Come back here, since here is where we live together. Here is where there is a person who loves you more than anything or anybody else in the world. So you come here. And I come here.”

  “You’re saying that Time takes its orders from love?”

  “No, no. I’m saying that Time takes us to the place where we want to go, if we have a place in mind. But here, where you are, where you live, that is the place that is always in my mind, so I only have to think of home and Time knows right where to take me.”

  “And you stay. You get off the treadmill to stay with me,” said Ivy.

  “The Prof can’t get off the treadmill for one very simple reason, which he told us himself.”

  Ivy thought only for a moment. “He never loved Mother Ivy.”

  “But when he’s in our time, the moment of our present, which really is his present, since the same amount of time passes for him as for—”

  “Don’t explain what I know, dear, get on with it.”

  “The reason he can slow down and stay in our time for at least a few minutes without getting swept away instantly, is not because it’s his ‘real time,’ it’s because he has returned to Ivy’s present moment.”

  “He doesn’t love her,” said Ivy.

  “But she loves him. Strongly, powerfully. It’s the magnet pulling him, keeping him here.”

  “This is too metaphysical for me.”

  “It is not,” said Laz. “Love brings me back to you—”

  “Because of the love in your heart, so it makes this place the most real destination—”

  “Love brings me back to you because it’s reciprocated. You’re looking for me, waiting for me, as much as I’m needing to come back to you.”

  Ivy laughed out loud. “Oh, Laz, listen to yourself.”

  “Romantic?”

  “Melodramatic. Fantastic.”

  “Yes, fantastic,” said Laz. “We can safely venture forth in time, because we will always draw each other back.”

  “So that whole shtick you did about not wanting us to be in love when we first woke up because we hadn’t personally earned it—”

  “I was an idiot. I was wrong. I was doubly wrong. I was wrongly wrong.”

  She kissed him lightly. “It’s so romantic to hear my man admit that.”

  “Ivy, how can we help the Prof?”

  “Not meaning to be brutish about this, Laz, but what’s it to us?”

  “Ivy, I lived his childhood. He’s partly me. Genetically, he’s completely me. I think he’s trapped in hell.”

  “And he’s desperate to get out,” said Ivy.

  “What are we supposed to do? Talk him into being in love with Mother Ivy?”

  “Yes,” said Ivy.

  “We don’t even like Mother Ivy—no, well, we like her now, but the Zees never did and still don’t.”

  “I believe,” said Ivy, “that the Professor was so quick to deny any feelings for Mother Ivy because he believed that for a man his age to get involved with a student was wrong. But she’s not a student now, and twenty years of age difference don’t mean squat when he’s eighty-odd and she’s sixty-or-so.”

  “You think all we have to do is give him permission to love Mother Ivy—”

  “And bring her to him, or him to her, so he can remember—”

  “He remembers the young Ivy, the one who looks like you.”

  “He remembers the worshipful Ivy, which Mother Ivy still is.”

  “And which you never are,” said Laz.

  “That’s because you haven’t done anything worth worshiping yet,” said Ivy. “But I have high hopes for you.”

  “Let’s take care of our assignments. You leaving a couple of messages for me, me leaving a message to the Zees. So we can assure our own existence. Then let’s see if love can bring the Prof home.”

  “Hinging everything on an emotion,” said Ivy. “Or maybe, a desire. A longing. A wish.”

  “I think that we should tell Mother Ivy what the plan is,” said Laz.

  “Absolutely not,” said Ivy. “She’s me, remember? So I’m telling you, if she thinks she’s expected to fall in love, required to do it—”

  “She’s already in love,” said Laz.

  “And then she’s rejected by the object of her love—”

  “She’ll feel betrayed,” said Laz. “By everybody who assured her that the Prof was secretly in love with her, if nothing kindles between them.”

  “Let’s not raise anybody’s expectations, so we can minimize the inevitable disappointments,” said Ivy.

  “It sounds as though we’ve planned out all the time travelers’ lives,” said Laz.

  “I’ll have to practice like you did,” said Ivy, “to be ready to go back and leave you those messages.”

  “It’ll come quickly, if you’ve studied your geography,” said Laz.

  “Shut up,” said Ivy.

  “And as long as you always remember to come back to me.”

  “Keep talking,” said Ivy.

  “Because I will always be here, reaching out to you, calling you home,” said Laz.

  “If this were an operetta, it would be time for the main love song,” said Ivy.

  “I once watched Naughty Marietta. Jeanette MacDonald and Nelson Eddy,” said Laz. “What was it, ‘Mystery of Life’?”

  “ ‘Ah! Sweet Mystery of Life,’ ” said Ivy, “but I’ve never seen the movie because Nelson Eddy had all the acting talent of a donkey. The operetta I was thinking of was ‘Indian Love Call,’ because I had a friend who collected old black-and-whites and I think I watched that a dozen times with her because she had to sing along with ‘When I’m calling you-ou-ou-ou-ou-ou-ou.’ She loved it, but she was never on the same pitch, so it gave me a headache.”

  “This isn’t an operetta, but we had two love songs mentioned, does that count?” asked Laz.

  “It has to,” said Ivy. Then: “Laz, I don’t want to die.”

  Laz shrugged. “I don’t want you to, either—”

  “Laz, I don’t want to die ever. This time travel thing, is there any chance that it can let us live on forever?”

  “I haven’t even thought of such a thing.”

  “Well I think of it. Not all the time, but it keeps coming up, and I try to think of a way to make it happen.”

  “Please don’t break your brain trying to stretch it to encompass the impossible,” said Laz.

  “We don’t know it’s impossible,” said Ivy.

  “We don’t know anything is impossible,” said Laz. “Time travel is impossible. Stepping between timestreams is impossible. We are impossible.”

  “That’s why I was hoping, why I hope—”

  “That impossible beings like us might do impossible things like living forever.”

  “But not as decrepit, demented old people,” said Ivy. “I was hoping that by traveling in time just the right way, we could stay this age forever.”

  “This is the perfect age?” asked Laz.

  “You look perfect. I feel perfect. Why not?”

  “After you deliver your messages to earlier-me,” said Laz, “why not get married when you come home?”

  “I thought you’d never ask,” said Ivy.

  “I asked a long time ago.”

  “I thought you’d never promise a day, a time. After I leave you your messages.”

  Then Laz realized something. “One message is, ‘Laz No.’ Is it telling me not to get married?”

  “It’s telling that heedless boy you used to be that whatever he was planning, he wasn’t ready to do,” said Ivy.

  “The other message isn’t ambiguous at all,” said Laz. “ ‘Go back no Portal here.’ ”

  “So you do remember it,” said Ivy.

  “But I didn’t get the message until I’d already made the Portal and buried the twine and the Portal is still there but the world hasn’t ended.”

  “So the warning that time was a teeny tiny load of crap,” said Ivy. “I don’t mind leaving you an unambiguous dumb message.”

  “So many hours trying to figure out what was meant by all three messages, and now to learn the messenger was just messing with us—”

  “The messenger,” said Ivy, “was keeping us involved, seeking, thinking, until we were ready.”

  “But now I’m ready?”

  “I’m certainly ready for you to be ready, Mr. Time Traveler,” said Ivy.

  “Then I’ll go leave the Zees their message right now, while you keep practicing short-hop time travel till I get back.”

  Ivy flew at him and kissed him long and hard.

  When the kiss finally ended, Laz complained, “Now I’ll be ten minutes late.”

  “But I’ll be much happier while I wait,” said Ivy.

  EPILOGUE

  Being called Mother Ivy was better than Ivy-O, but it also pricked her heart because she was not a mother. Just because she had two clones who were younger than her did not make her feel motherly—they had come full-grown into the world, so she had had no part in the raising of them, apart from the fact that they had all her childhood memories.