Even though he visualized the strands of the timestreams being right in front of him, he had always felt as if he moved to the side when he took hold of a timestream. He didn’t go forward or backward in time, he simply arrived in the new timestream at the exact moment he left the other. Time flowed in lockstep, as far as Laz knew, and Ivy had no contrary evidence in her experience, even now that she could, with difficulty, take a side step of her own.

  By agreement, they tried never to side step alone, for fear that they would choose different timestreams and become irrevocably separated. Not that Ivy didn’t always know where Laz was, what timestream he was in, and he could track Ivy, too, though not as easily and not as quickly. But Ivy-O had lost OrigiLaz, hadn’t she? So they couldn’t be sure that they wouldn’t lose each other in the streams of time. The strings, the threads, the drizzles of time.

  Those timestreams. In Laz’s mind, he visualized himself reaching out and taking a timestream in his hand, and then he would side step and be in the new stream. But he didn’t really use his hand, it’s just the way his brain made sense of these impossible senses.

  But was there some way that, instead of taking hold of the new timestream in the moment called “now,” he could reach higher up and take the timestream at an earlier time? Would a side step then take him to an earlier point on the timestream? Yesterday, last year, a hundred years ago? What if a version of himself existed in that timestream already—a younger version of himself—and he side stepped into that body instead of taking his own body with him? How would he figure out what was going on? It might be okay in the middle of English class, but not on a date. And what if he had only the memories of the Laz he stepped into? Then he’d be trapped, reliving half his life with no memory of how things would turn out or how he once made them better.

  What if he stepped back to the time when he and Stever were doing ridiculous, harmful, dangerous pranks? He had side stepped out of those timestreams and kept himself from meeting Steven Weaver, so they never goaded each other into their mutual stupidity. But what if he forgot that maneuver and stuck with one of the awful timestreams, the ones with prison time for putting a bomb in the principal’s car, endangering nearby students?

  The dangers of it weren’t enough to make Laz think that this method of time travel couldn’t possibly work. It might not work well, he might not be happy with the results, but if there was some way to travel upstring into an earlier time by grabbing the timestream higher—

  Wouldn’t he have already found it?

  Maybe there was some resistance to moving out of your own moment into an earlier one, so you wouldn’t accidentally do it. And OrigiLaz had found a way to overcome that resistance, and suddenly he was no longer in the Now, and so Ivy-O couldn’t find him because now he didn’t exist in the Now.

  This was the kind of thinking that was filling his mind when his bedroom door opened and soft footsteps entered. “If you’re an assassin, make it quick and don’t mess up my face, I want an open-coffin funeral.”

  Ivy chuckled. “Worst-case scenario just pops into your head, eh?”

  Laz opened his eyes. In the dim illumination from a streetlamp fudging its light around the edges of the window curtains, he could see that Ivy was not here to make some indecent proposal, as had happened now and then in the past. She was fully dressed, at least in pajamas.

  Then she pulled down the covers and slid into the bed beside him.

  “Come on, really?” Laz asked. But secretly he was thrilled and excited. It’s not that he didn’t long for her all the time.

  “I need to talk, you’re awake, it’s a little chilly and I want to stay warm while we talk. So keep your pants on.”

  “I wasn’t going to—”

  “You’re male, I’m female, we kiss a lot, shut up. I’ve been trying to puzzle all this stuff out, and it isn’t working.”

  “Have you ever tried grabbing a timestream higher up? In the past?” asked Laz.

  “Yes, I’ve thought of it. No, I haven’t tried it because what if it worked. Would I have to relive grade school all over again? Or would I find myself in the world before I was born, and there I’d be without money—not money I could actually use, in denominations anybody could deal with. No credible ID, since driver’s licenses are rarely issued with expiration dates a century later. My clothes would be regarded as weird—I mean, what if I went back to a time before brassieres were invented? And what about feminine hygiene products?”

  “And fluoride toothpaste. And penicillin. Calvin Coolidge’s son died from an infected scratch he got playing tennis, something penicillin could have dealt with instantly. Winston Churchill’s dad might have had syphilis from a drunken prank his so-called friends played on him, so he died young. And I wouldn’t be immune to gangrene or any of the other diseases that we aren’t vaccinated for these days,” said Laz.

  “So you’ve thought about it, too.”

  “All sorts of reasons not to go back in time. Impractical. Not to mention changes in the language, so we might not be able to communicate with anybody.”

  “Maybe we could muddle our way through those inconveniences,” said Ivy. “But there’s the physics question—would inserting ourselves into the past mean a net gain of mass in the universe?”

  “Not a very big one,” said Laz.

  “But mass that had not existed before,” said Ivy.

  “ ‘Matter and energy cannot be created or destroyed,’ ” Laz intoned.

  “And if we went back in time, would the timestreams available to us then reach far enough into the future for us to return to the time we left?”

  Laz hadn’t thought of the return trip yet. “Even if they did, the strings aren’t calibrated, so how do we know when we’ve found the time we left?”

  “And would we age during these jaunts? I can’t think why not. So we might come back to the present ten years older than we were a minute before.”

  “That could be really sad for you,” said Laz, “since girls age faster.”

  “Girls mature faster,” Ivy corrected him, smacking him on the hip under the covers.

  “Hey,” said Laz. “No hitting.”

  “Then no insulting,” said Ivy.

  “Just because you don’t have a sense of humor tonight—”

  “Does this stuff matter or not?” asked Ivy. “Somebody’s moving around in time—maybe—and we’re entirely at their mercy. If they can silently, suddenly, invisibly write a message in the dirt, what stops them from pushing a blade into our hearts? Setting us on fire?”

  “So far the messengers seem to be trying to help,” said Laz. “But yes, we might be in danger if they get, like, mad at us.”

  “Maybe the messages came from us,” said Ivy. “Future us.”

  “Then wouldn’t us have been nice enough to sign the notes?”

  “It would certainly have spared us at least some of our confusion,” said Ivy.

  “But we know that if we’re the time travelers, we will not sign the notes we leave for us, and we know that because we didn’t.”

  “In the past,” said Ivy, “which is also our future, if we can travel in time.”

  “Weren’t we crazy enough already?” asked Laz.

  “Ron’s people are probably listening to this,” said Ivy.

  “We’re the best show on this late at night,” said Laz.

  “Not much of a show,” said Ivy. And then it occurred to her. “What if we did have sex tonight? Would they stop watching and listening so we could have some privacy?”

  “Would you stop?” asked Laz. “If you were one of the watchers?”

  “I’d stop watching,” she said. “But I’d probably keep listening.”

  “Recording it all for Ron to enjoy later,” said Laz.

  “Do you talk dirty during sex?” asked Ivy.

  This really exasperated Laz. “How would I know?”

  “Never heard you talk dirty. Or cuss much,” said Ivy. “So, probably not.”

  “Well, good,” said Laz. “That means that if we ever have sex, they won’t have to bleep out all my bad words before Ron hears them and gets shocked.”

  “Do you even know any bad words?” asked Ivy.

  “I know them all,” said Laz. “I went to middle school. But I hung out with people who didn’t use ugly words for punctuation. Never picked up the habit.”

  “All my friends cussed like those words were common prepositions,” said Ivy. “I don’t know if any of them even thought of those as bad words in the first place. Just… the language that they learned at home.”

  Laz chuckled. “You know what that means. If they got Tourette’s syndrome, there wouldn’t be any list of unspeakable words in their heads. That would be a real bummer, to get Tourette’s and have nothing to say.”

  Ivy chuckled, too. “Laz,” she said, “do you think Ron’s people have done any research to find out the long-term psychological damage caused by being continuously observed?”

  “And knowing that you’re under observation,” said Laz.

  “As far as I can tell, we just put up with it and pretend it isn’t happening, except now and then when we remember, and by then we’ve already said too much,” said Ivy. “I don’t feel particularly damaged.”

  “Would we even know that we were damaged?” asked Laz.

  “Would that matter?” asked Ivy.

  “If you lost a leg, but great anesthesia made it so you never knew about the operation, believing you had two good legs wouldn’t help you one bit in walking.”

  “Laz,” said Ivy, “why is this our job?”

  “Figuring out what’s going on?” asked Laz.

  “I mean, we’re supposed to be tending the Portals, and maybe we got carried away, trying to open some secret ones, but our job isn’t figuring out time travel or invisibility.”

  “It became our job when somebody somehow left us those messages.”

  “First,” said Ivy, “they didn’t leave us those messages, they left them for you.”

  “Only because I was the one about to screw up,” said Laz.

  “Or because you’re the real side stepper, and only you will be able to move through time,” said Ivy.

  “Great,” said Laz. “Let’s get resentful about my infinitely superior gifts before we even figure out whether I have any.”

  “If we, or OrigiLaz, or the Zee kids have been traveling in time,” said Ivy, “why haven’t they cleaned up history a little?”

  “Killing Hitler?” asked Laz.

  “No way to control the outcome. For all we know, Hitler kept somebody even worse from becoming dictator of the world,” said Ivy.

  “Then what would they clean up?”

  “Little monsters instead of the big ones. Finding a serial killer or a mass murderer and…”

  “And what?” asked Laz. “We aren’t murderers.”

  “I just thought, what if they left the serial killer a note. Like, ‘Jack the Ripper, stop.’ Or terrorist bombers, or aggressive morons who didn’t actually conquer Europe. ‘Building an empire never ends, you always gotta make it bigger.’ ”

  “Pretty long message to scratch in the dirt,” said Laz. “And I don’t know if Napoleon or Pol Pot or Lyle Bong could even read English.”

  “Bong was Australian,” said Ivy.

  “Oh, they teach their kids to read down under?” asked Laz. “Anyway, none of those people would have obeyed an anonymous message.”

  “A message that appears from nowhere, right before your eyes?” asked Ivy. “It would at least make them think twice.”

  “Or instantly convert them from their evil ways, once they knew that God and his angels were watching,” said Laz.

  “Laz, you know you’re going to try to go back in time.”

  “I don’t know anything of the kind,” said Laz.

  “Well I know that you won’t rest until you get some answers, and learning to time travel is one way to get those answers, so yes, I know you’re going to try it.”

  “And then I fail, and so what?” asked Laz.

  “A, you won’t fail, and B, even if you do fail, you’ll just think you did it wrong and keep trying. Like throwing stones at a target to find a way to drive away hungry dogs.”

  “But I knew stone-throwing was actually possible,” said Laz.

  “But you didn’t know if accurate stone-throwing with enough force to hurt was something you could ever acquire the skill to do.”

  “And I didn’t become, like, baseball-pitcher good at throwing.”

  “You got dog-damaging strength behind it, and accurate enough to hit a moving dog.”

  “Don’t count on my having those skills now. It was Z-Laz who did that. I didn’t inherit any muscle memory from him.”

  “Have you tried throwing a stone to find out?” asked Ivy.

  “I don’t have the Pack of Four stalking me,” said Laz.

  “What have we decided here?” asked Ivy.

  “Well, you decided to crawl into my bed and hit me,” said Laz.

  “About time travel. We agreed that you’re stupid enough to try it, to see if we can use the timestreams to do it.”

  “You agreed that. I didn’t even vote.”

  “And we thought of some of the stuff that could go wrong,” said Ivy.

  “And we kind of ruled out the idea that it’s our future selves leaving these messages,” said Laz.

  “Did we?”

  “Because we would have signed the messages,” said Laz.

  “Unless there was some compelling reason not to,” said Ivy, “which we haven’t thought of yet.”

  “So we don’t actually know anything,” said Laz.

  “I like having pillow talk with you,” said Ivy. “Maybe now I can go to sleep.”

  “Well, I hate it,” said Laz, “because now I probably won’t go to sleep for hours.”

  “Why?” asked Ivy. “Talking things through can really ease your—”

  By then, Laz had one arm across her body, holding him up as he planted a pretty convincing kiss on her mouth. She was surprised, but she kissed him back. When he released the kiss, he stayed in place, hovering over her, eyes locked and lips still ready. “My mind is not eased at all,” he whispered.

  “Your mind had nothing to do with that,” said Ivy, also very softly.

  “My mind is the reason we still have clothes on,” whispered Laz, his lips now brushing hers. “So it was very much involved.”

  She kissed him, lightly, briefly, several times. “You’re saying that pillow talk doesn’t help you get to sleep.”

  “Pillow talk with one’s beloved is not restful,” said Laz softly, “unless it comes after.”

  She leaned her head forward and kissed him long and hard. “But I bet ‘before’ would still be pretty good,” said Ivy, “even if it came after the pillow talk.”

  “Is that an offer?” asked Laz.

  “Do you want it to be?” asked Ivy.

  Laz rolled back onto his side of the bed. “I don’t think it’s a good idea,” he said.

  “I know you want to. You can’t hide that,” said Ivy.

  “Not trying to hide anything,” said Laz. “I don’t want you to think I don’t want you.”

  “But you don’t want me.”

  “Stupid female,” said Laz. “And I mean that in the nicest possible way. Stupid female, I want nothing but you. No food, no entertainment, no work, no curiosity about the mysteries, no world-shaking scientific discoveries, Nothing but you.”

  “And yet here I am, and here you are.”

  “Let’s not do this again,” said Laz. “Not until we both agree that it’s time. Like, after we get married.”

  “Is that a proposal?” asked Ivy.

  “Of course it is,” said Laz. “It’s not as if we really needed one, with the Zees to show us that a couple as loathsome as ourselves—except you, of course—can find true happiness in marriage.”

  “A girl still wants to hear the words, even from the smartest guy in the world.”

  Laz rolled over and sat on the edge of the bed. “I was hoping you’d want that proposal from me.”

  “I meant you,” said Ivy.

  “It’s OrigiLaz that everybody thinks was so smart, though I doubt it a lot. He’s the one who vanished, and he belongs to Ivy-O anyway. I hoped you wanted me to propose.”

  “Whose bed was I lying in?” asked Ivy.

  “Whose bed did you wish you were lying in?” asked Laz.

  “We stopped whispering, so Ron is hearing all of this,” said Ivy.

  “Yeah, they’ve never heard us fight before,” said Laz.

  “This was a fight?” asked Ivy.

  “I think so. We disagreed.”

  “We agreed completely,” said Ivy, “except the part where you still said no.”

  “I didn’t say no. I asked you to marry me.”

  “I never heard those words,” said Ivy. Now it was her turn to sit up on the edge of the bed, her back to him, his back to her. “This bed feels a hundred meters wide right now.”

  Laz knew exactly what she meant. He longed to lie back, pull her down beside him, on top of him, and spend the rest of the night holding her. Instead he said nothing, did nothing.

  She got up from the bed and walked out of the room. She did not close the door behind her. Laz wondered if that meant she hoped he would follow her. But he wouldn’t follow her, and he figured she probably knew that.

  And now Ron would know that Laz was so crazy that, with a beautiful and willing lover in his bed beside him, he said no, he did nothing, or nearly nothing, and let her walk out of his room.

  Laz’s prediction, however, was wrong. He got to sleep very quickly after she left. Because talking things through with her really had set his mind a little more at ease. Now he knew what he had to do. But he’d do it tomorrow, when he was fully awake.

  Before he dropped off, though, he did scan the nearby timestreams, to see if he and Ivy actually made love in any of them. Not that he would side step into that stream, not at all, he just wanted to know if there was a version of reality in which he followed his heart instead of his head.

  Nope, not a one. He was a monster of self-denial in every possible causal universe.