He could imagine her saying, “I know you so well I got up to that spot before you, while you were twinking around with the first Portal, and left that message just to see if you’d notice. You were more observant than I imagined.”

  But she didn’t know him that well, nobody knew anybody that well. It wasn’t her. And he needed her to help him figure out who left the warning and why. Did it apply to that Portal, in that spot, at that time? Or did it apply to the whole project of making secret Portals?

  Maybe the message meant, Laz. No. So that whatever he was thinking of doing, he wouldn’t do it.

  The message led with his name. The scratcher-of-messages knew that someone named Laz would come to this spot and would see the message No. How could they know that?

  He turned his wrist so his watch could take a picture of the message. And then a closer one. Since he was still in Ron’s central timestream, and Ivy was too, it was a good idea to have it upload to the cloud, so if he got killed or lost Ivy would be able to download the picture and maybe get some idea of what was happening. Or Ron might do it. They probably checked Laz’s and Ivy’s cloud storage all the time.

  Laz picked up his bag, left the twine he had tied to a tree but had not yet connected to anything else, and started the long walk back down to the ski lodge.

  8

  IVY WAS DOING some kind of project that had her squinting over something in her lap. Not reading, the usual activity that made her squint. He remembered that last kiss before he left. How can I keep pretending I’m not in love with her? Laz did like to look at her. But he worried about her eyesight.

  “They still make glasses, you know,” said Laz. “Spectacles. Even monocles. Or contact lenses. And there’s about six different laser procedures.” Halfway through this statement he realized that his tone had the bratty sarcasm that they had used back when they were not willing to admit their mutual attraction. It was disrespectful. It was hurtful. It was wrong. But he finished the statement anyway, because it would be too embarrassing to stop in the middle and apologize. Or beg forgiveness, whatever it took.

  Maybe she didn’t even notice his sarcasm.

  Ivy raised her head and looked at Laz standing in the door. She decided to smile, and then she did; Laz would rather she had smiled without having to decide to do it. “Back so soon?” she said. “I thought you had at least a month’s work ahead of you. Solving the deepest riddles of space, time, and causality deserves at least a week of concentrated effort.”

  Yeah, she had heard the sarcasm and answered in the same manner. He decided to change his tone. “I wasn’t doing any deep thinking at all,” said Laz. “I was opening secret Portals to problematic timestreams. And something happened that made it impossible for me to go on without talking to you.”

  “It’s nice to feel needed,” said Ivy.

  I do need you, thought Laz. If you had been there, you could tell me whether I really saw what I thought I saw. “You should have come with me,” he said. He would have explained why he wished she had been there, but her riposte was immediate:

  “And miss out on all my embroidery practice?”

  Laz looked at what she was doing. A hoop or frame or something, with coarse ecru fabric stretched tight, and lines of thread doing… whatever thread does when it’s not stitching two edges together.

  “My grandmother taught me. All summer one year,” said Ivy. “She insisted I wear a skirt—‘a young lady should dress as a lady; everybody can see that she’s young’—and so, without realizing it, I stitched my embroidery right to my skirt as well as my fabric. I had to unpick the whole day’s stitches. And she said, ‘Good work,’ and I said, ‘I had to unpick every bit, this whole morning was wasted.’ And she said, ‘Was the stitching good? Did it look nice and even? Or ragged and loopy?’ I told her it looked better than I expected, but not as good as it would look when I redid it.”

  “The ideal student, you were, as always,” said Laz.

  “She was my grandmother and I wanted to please her more than anybody.”

  “But she was not disappointed in you, right?”

  “No,” said Ivy. “It took me years to understand why. Nana said, ‘Unpicking wrong stitches is as much a part of embroidery as stitching. Lazy embroiderers leave their mistakes and say it gives their work character, so people will know it was made by a human. But you are a human, and you can learn to be both perfect and expressive. The machines never do either. All they do is “good enough.” Good enough for who, ask I. Good enough for the kind of people who wouldn’t know “good” if they gave birth to it and raised it from a child.’ ”

  “Do you miss her?” asked Laz.

  “My memory tells me I did, so I still do. But by your standard it wasn’t me, not in this body, who knew her. She must have died before we ever met as Ivy-Z and Z-Laz.”

  “We have memories like those of old people—our childhood clear as a bell, but no idea what’s happened in the past twenty years.”

  Ivy held her embroidery closer to her eyes. She was trying to push the embroidery needle into an already crowded patch of fabric. Laz remained quiet while she performed her delicate operation.

  He knew Ivy was finished when she gave a barely audible yelp and pulled her other hand out from under the hoop and put a finger in her mouth.

  “I’m so sorry,” said Laz. “Do you need some antiseptic?”

  “What have you got? Rubbing alcohol? Spit from a dog’s mouth? Neosporin? Tincture of iodine? Merthiolate? Essence of urine?”

  Didn’t she know that Laz was being genuinely sympathetic? Why was she mocking him? Was she ridiculing him? Or just playing with the idea of antiseptic for her stabbed finger? Covering for her own embarrassing self-wounding?

  Ivy looked at him, pulled the finger from her mouth, and said, “Why are you back so soon?”

  “Don’t you see my discarded timestreams?”

  “Why should I look, considering that you’re dying to tell me?”

  “I need you to help me make sense of it,” said Laz. Laz got a glass and filled it with lemonade from the fridge.

  “It’s nice of them to keep the fridge stocked,” said Ivy.

  “Nothing they do is ‘nice,’ ” said Laz. “They always have a purpose.”

  “The purpose of good manners is to make the other person comfortable,” said Ivy. “That lemonade is making you more comfortable, right? So they were nice to you.”

  “And therefore I’m in their debt,” said Laz.

  “We both owe our existence right now to Ron’s people. If they hadn’t created us—”

  “We’re going to do the jobs they made us for,” said Laz. “That will fully discharge any debt we have to them.”

  Ivy set aside her embroidery, using her unpricked hand. “It doesn’t enhance the needlework to get blood on it,” she said. Then she resettled her position so she was facing squarely forward. “What is it you are so eager-as-a-guppy to tell me about?”

  Laz resisted the temptation to correct her “guppy” to “puppy.”

  He might as well have said it. Ivy responded as if he had. “Guppies are never eager? You’re sure of that?”

  “I was eager, but that’s because I thought I was going to be seeing the Ivy who isn’t snippy to me.”

  “And here I thought that Snippy was our love language.”

  “Not mine,” said Laz.

  “In Greensboro, Kissy Girl would have jumped up and thrown her arms around you and kissed you before you could get through the door—that was a different Ivy, as you say. So I’m trying to work out what this Ivy ought to feel about this you.”

  “You should feel interested when I tell you that something important happened, something I wish you could have seen for yourself, something that you definitely want to know about no matter how you want to punish me for questioning the reality of our legendary love.”

  She framed a sharp retort and then didn’t say it. Instead she moved her embroidery farther aside, and as she stood up she said, “See? I didn’t sew it to my clothes this time.”

  “I’m proud of you, darlin’ girl,” said Laz, thinking he was speaking as her Nana might have spoken to her.

  But “proud of you” was said into her hair, because she came to him and wrapped her arms around him and stood on her toes so that her hair was right there by his mouth. When he finished his sentence she kissed him. Long and sweet.

  He was not the one who broke off the kiss.

  “That was your I’m-glad-you’re-back kiss,” she said.

  “What I was giving you was a heartfelt declaration of love,” said Laz. “Present love, not remembered love. But you were being Kissy Girl, who tried to win me over in the lobby of Vivipartum.”

  She shook her head, smirking. “That wasn’t you who got kissed at Vivipartum, it was Z-Laz. You remember it, but you never did it.”

  “Okay, yes, right, I’m an ass.”

  “It has been my lifelong ambition never to kiss ass,” said Ivy.

  “I was a fool.”

  “Was?”

  “I am a fool,” said Laz. “So many times I’ve wished this were how it still was between us.”

  “You really are a jackass,” said Ivy, “and now I’ve kissed you, and we’re probably going to think everything is going swimmingly between us, when in fact everything is broken and that kiss was a Band-Aid on a broken hip.”

  “With a stinging antibiotic on the wound,” said Laz.

  Ivy nodded ruefully.

  “Here’s what happened,” Laz began.

  Ivy sat back down and patted the couch beside her.

  Laz accepted the invitation and sat down beside her. “I made one Portal in the woods and walked a ways and I was tying twine onto trees so I could make another Portal, and when I turned around, there was a patch of dirt swept clean of dead leaves, maybe a meter square, probably less. And right in the middle it had writing that said, ‘Laz No.’ ”

  “So they knew you were coming there? They saw that far into the future?” asked Ivy.

  “It wasn’t there when I walked into the clearing,” said Laz.

  “You mean you didn’t see it,” said Ivy.

  Laz held out his phone. “Here’s the picture I took of the clearing just before I walked in. No cleared patch.”

  She looked at it for a while. Probably making sure that the cleared patch really wasn’t there.

  “It really wasn’t there till after I walked past it,” said Laz.

  “I don’t doubt you,” said Ivy. “I was hoping to catch a glimpse of somebody lurking in the underbrush, waiting to scamper out and clear that patch when your back was turned.”

  “I couldn’t see anybody either,” said Laz.

  “Do you have a picture of this ancient inscription you stumbled upon?”

  “It’s in Mayan glyphs, but I’m sure you can read it pretty easily.” He advanced a few pictures and showed her the one he took from directly over the writing.

  “These are English letters, Laz, not Mayan,” said Ivy, gently, as if she didn’t want to embarrass him.

  Laz spoke as if he was really disappointed. “And here I was happy because I thought I could read Mayan.”

  “What does it mean?” asked Ivy.

  “I took it to mean I shouldn’t do what I was about to do—side step into one of the settled worlds.”

  “But why? If there was some ambush set, you would have seen it in the timestream and not stepped into that one.”

  “Maybe my making a Portal there would lead to war, or a plague that spread between the worlds, or just me being caught and a huge scandal erupting about how Ron’s people were spying on the ‘independent’ worlds.”

  “Which I’m sure they do,” said Ivy. “But you and I aren’t ‘Ron’s people.’ ”

  “Nobody understands that,’ said Laz. “Not even Ron.”

  “So did you make the secret Portal anyway?” asked Ivy.

  “Of course I didn’t make the Portal, because I didn’t have enough information to be sure I wouldn’t risk a huge change between the worlds.”

  “So who was warning you or stopping you?” asked Ivy.

  “That’s why I needed you with me. So we could talk about it.”

  “How did they know you needed to be stopped, and where to do it?”

  “And how did they get into the clearing to write that message without my seeing them or hearing them?” asked Laz.

  Ivy nodded. “Somebody who can really see into the future, I’d guess,” she said.

  “Or somebody who’s been visiting the future and came back to warn me,” said Laz.

  Ivy chuckled and shook her head. “Seriously, Laz? Side stepping doesn’t shift you in time, it only changes the situation you find yourself in.”

  “So far,” said Laz.

  Ivy thought long and hard about that one. “Okay, that’s a good question. How do we know time travel isn’t possible?”

  “We don’t know that,” said Laz. “There are lots of problems and paradoxes with causality being shifted in both places, so nobody has ever figured out if it’s possible.”

  “Philosophers can settle for opinions,” said Ivy. “Scientists can’t.”

  “And yet so often they do,” said Laz. “You can’t find the truth by polling scientists.”

  “So all we know is that it isn’t possible for us. So far,” said Ivy.

  “As long as we’re playing with impossibilities, let’s say they also know how to make themselves completely transparent to light, so they can’t be seen unless somebody already knows exactly where they are.”

  “Time travel. Invisible people.”

  “And soundless, too, or I would have heard that sweeping away of dirt.”

  Then Ivy spoke with some authority in her voice. “It has to be that somebody was following you.”

  Laz wanted to say, Do you think I didn’t think of that? But instead he let her think that he was thinking about it. Then, quite reasonably, he said, “I was only there for thirty seconds. Or less. They couldn’t have been close enough behind me to walk in, write the message, and leave without my seeing or hearing them. Unless you think they have a cloak of silence and invisibility.”

  She sighed. “We can’t think of anything useful unless you stop rejecting every cause that’s actually possible,” said Ivy.

  “I reject them,” said Laz, “because the only eyewitness—me—did not see or hear them.”

  “So if my ideas are all wrong,” said Ivy, “why did you need to come home to talk about it?”

  “The problem isn’t you,” said Laz.

  “That’s a relief.”

  “It isn’t me either,” said Laz. “Somebody did something impossible, so the key isn’t looking for a reasonable explanation, the key is finding out which insane hypothesis might actually be right.”

  “Maybe the most vital question isn’t how, it’s who,” said Ivy.

  “Like?”

  “If I knew, I’d—well, maybe Z-Laz and Ivy-Z, one or the other or both of them.”

  Laz shook his head. “They’re the only people around who can match what we do. But can they surpass it?”

  “Ivy-O gave up on the science long ago,” said Ivy.

  “She always left the science to Professor Lazarus,” said Laz.

  Ivy smiled a Cheshire cat smile and looked at Laz expectantly. “You’re the only Lazarus Hayerian I’ve got.”

  “I’m not the Professor yet,” said Laz. “But there’s a way we could bring this about without any actual time travel at all.”

  Ivy pulled her legs up under her and faced him on the couch. Apparently waiting for pearls of wisdom to fall from his lips. Then she said, “Are you still awake?”

  He startled, and realized that he might actually have dozed off for a moment.

  “Sorry,” said Laz.

  “You need to sleep. Let’s continue this later.”

  “We were getting close to something,” said Laz. “Now it’s gone.”

  “You said there’s a way without time travel,” said Ivy.

  Laz remembered now, with that prompting. “Look, let’s say it’s Z-Laz and Ivy-Z, a year from now,” said Laz. “They can see that my making that Portal brought calamity down on the whole timestream. So together, the Zees scour the timestreams looking for one with a different outcome—an acceptable outcome, maybe even a good one. So they side step to that timestream, where everything worked out okay.”

  “And that happened to be the timestream where somebody had written, ‘Laz No’ in the dirt?”

  Laz wanted to say, Now who’s shooting down ideas? But he knew her objection was the clincher. “Maybe if we often stumbled on timestreams where somebody wrote random dirt-epistles that coincidentally seemed to apply to us, we could imagine this as being just another example of that,” said Laz.

  “But we don’t ever,” said Ivy. “And no matter what, messages don’t spontaneously crop up like fairy circles in random clearings in the forest. Somebody wrote that message, and it was directed at you.”

  “Unless I happened to be the wrong Laz popping up at the wrong time.”

  Ivy smiled. “Let’s leave that set of remarkable coincidences to consider at another time.”

  “Like after I’m dead,” said Laz.

  “But the idea of choosing a timestream where it happened would remove the need for time travel,” said Ivy.

  “So future us, or future Z-Laz and Ivy-Z,” said Laz, “suppose they know exactly what needs to happen in that timestream, and by concentrating and searching hard, their combined will goes back to that moment and causes it to happen.”

  Ivy thought a few moments. “It’s still time travel, Laz. Even if nobody actually travels into the past, future Laz-n-Ivy would still be causing change in the past, reaching back and influencing it. They’re creating the alternate past they need to find.”

  “But what if it could happen?” asked Laz.