“Well, the only thing I know is that these things are really far outside of how stuff works. I don’t want to say ‘aliens’ because I don’t know anything. But it doesn’t seem possible that this was done by any man-made technology, and it certainly didn’t happen naturally. Like, the Carls didn’t grow from seeds. So the vaguest, most general thing I can say is ‘external origin.’ Meaning, basically, this doesn’t make sense.”

“So you’re not saying Carl is a space alien.”

“No, but I am saying it looks increasingly likely that the Carls weren’t made by humans or by nature.”

“So you are saying Carl is a space alien!” I started to freak out again.

“No, I . . . I don’t know, April! It’s exciting, but space aliens are a very specific explanation for a very broad circumstance. There’s more to the universe than humans and aliens. Maybe they’re made by humans but sent from the future. Maybe they are a kind of projection through space-time. Maybe they’re proof that our universe is a simulation and someone is changing the code. Mostly, I don’t pretend an explanation is correct just because I haven’t thought of any others that fit with current data.”

She seemed very sure of herself, even if she looked a little timid and freaked-out talking to me.

“Well, Miranda, speaking of the current data. We haven’t told anyone about this, but there’s more.”

Her eyes, impossibly, got bigger.

I took her through the procedure of the Wikipedia clue.

“This is deeply impossible,” she said after we had gone through the whole sequence, “and nonsensical as well. I-A-M-U.”

“I know. I’ve been racking my brain over this for days, so I don’t expect you to—”

“Elements,” she interrupted.

“What?”

“Elements. I, Am, U—those are all elements. Iodine, americium, uranium.”

“OK, that’s another lead to add to the fifty-mile-long list of guesses as to what this might mean.”

She looked a little dejected, and I felt bad for immediately dashing her first try at explaining it. I mean, of course Miranda would find a sciencey explanation—she did sciencey stuff. So I said, “I mean, that’s interesting, though—we hadn’t thought of it.”

Her smile came back.

“So does this Wikipedia thing make . . . your hypothesis more or less likely? Also, is there a time when we’re going to know for sure?”

Her eyes shot around in thought for a moment before she said, “The Wikipedia thing is weird, but less weird than the material thing. But maybe that’s just because I don’t really know that much about how the internet works. I’d have to talk to someone who knows things I don’t know. But the material is not only unknown technology; according to my understanding of physics, it’s not possible. And your second question is a great question. I don’t know when we will know for sure. Maybe never. Sometimes there are mysteries that linger for centuries. So I don’t know. I just can’t fathom another explanation.”

We sat there and stared at each other for a long time before she got too uncomfortable and just said, “So . . . uh . . .”

“So do you suggest operating under the assumption, privately at least, that Carl is . . . external?”

“It’s hard to say, right?”

“It is.”

Saying that felt weirdly like cursing in church. I wasn’t quite in shock; I was more feeling like I must be an idiot for even listening to this.

Miranda continued. “Sometimes we have to do that. Sometimes we have to go with an imperfect theory and . . .” She got quiet and her eyes unfocused and moved around the room. I stayed quiet because it seemed like if I said something I would be interrupting something intimate and sacred.

“April, what if Carl’s asking for something? Like, they want us to bring them things. None of those elements are abundant. Maybe they need something!”

I was, to be clear, completely clueless. For Miranda, things appeared to be crashing into place faster than I even got my mind around the fact that this might be a for-real thing that Carl was doing. That Carl was alive. That Carl was . . . external. I did my best to keep up.

“But, well, we’re not going to be able to give Carl uranium.”

“Why not?”

“Well, it’s uranium. Doc Brown tried to get some and the terrorists shot him.”

“That was plutonium, and in any case, it’s all a matter of quantity. Iodine is easy—we’ve got that in the lab. Uranium I don’t have, but you can buy unrefined uranium ore on Amazon—it’s not dangerous unless it’s purified. Americium, though, I don’t know much about. It’s transuranic, so radioactive and rare. I’ll have to do some research. Quantities and purities are the hard part with rare stuff.”

She fired this all off at rapid speed, and as soon as she hit “do some research,” I could hear her typing while she talked.

“OH! I’ve got a lead on americium,” she said after a tiny pause. “It’s in most smoke detectors, so you can literally buy it at Walmart.”

“Miranda, is it possible that Carl doesn’t want uranium? I’ve already started to get questions from people who think that they’re dangerous. Probably wouldn’t be good for their image if they’re searching for radioactive materials.”

“I mean, I dunno, it was just a thought.”

I felt bad for throwing a wrench into her beautiful brain machine, though I did kinda want to slow the conversation.

“I mean . . .” I wanted to encourage her. She was hard not to like, almost like a kid. A genius kid. “It could be. I just thought maybe we should be a little surer before we start stockpiling uranium.”

Again, she was typing while I was talking.

“Oh god,” she said, seeming scared. And that made me scared. It was the first time I thought maybe the Carls were indeed here to hurt us. Like she had discovered that mixing americium, iodine, and uranium would make a bomb that would destroy the earth.

“Is everything OK?”

“Shhhh.” She shushed me. She shushed me like I was a five-year-old who wanted a Popsicle and she was on the phone with a very important client. She was clicking and typing and clicking and typing. I just sat there because, obviously, Miranda was hitting this problem way harder than I had the ability to. After a full minute of me being completely silent, she picked up exactly where we had left off.

“HAH!” she shouted. I startled. “Sorry! Yes! Omigod, April, I am so sorry. I shushed you. Oh god.” She was turning red, and then she seemed to remember other things were going on. “April, everything is fine. But Carl definitely meant elements when he said ‘I AM U’ because everything on this Wikipedia page has reverted to normal except the original typo . . . and about”—and here she started frantically scribbling in pen on her own hand—“nine numbers from the citations. Nine numbers are gone.”

She held up her hand, on which was scribbled, “127243238.”

“How did you figure that out so fast?”

“I have a proxy IP set up so I can watch BBC shows. I was able to open the page from my IP and a British IP simultaneously. Comparing was easy once I noticed numbers were missing.”

“OK, so what is it? It’s not enough numbers for a phone number.”

“Hah . . . no. They’re the most common isotopes of those elements. Iodine-127, americium-243, and uranium-238. Do you know what an isotope is?”

“No, but maybe I don’t need to?”

“No, maybe not right this moment. Suffice to say, Carl is asking for elements, and though there are more common elements out there, he’s asking for the most common isotopes, which, if we’re going to be his couriers, makes our job easier.”

“Are you for real right now?”

“In what ways?”

“Did you just, in five minutes, solve a puzzle that has been devouring every ounce of my mental energy for the last two weeks? I can’t believe I never looked at the citation numbers!”

“No one ever looks at the citations, don’t worry. Sometimes you just need a fresh pair of eyes.”

“Yeah, a pair of eyes that have heard of americium.” I didn’t even know that americium was a thing. It was another few days before I saw it written down and realized it was an element named for America, since it’s pronounced like “amer-ISS-ium.”

“Eyes can’t hear, April! So you’re on TV tonight, right? That’s exciting.”

“OH MY GOD NO IT’S NOT!”

She grinned. “Yeah, I guess not.”

“Hey, Miranda?”

“Yeah?”

“You want to go to Walmart with me?”

* * *

    It was midnight. Our show was on TV, but now that seemed like the least interesting thing in the world. The mystery had eclipsed my obsession with strangers analyzing my performance. I had made a date to meet up with Miranda. She would drive down from San Francisco to meet me at Hollywood Carl after our fancy agent meeting. She was excited to meet Andy as well.

I got into the big, silky, soft, cool hotel bed and turned off the lights and stared at the insides of my eyelids for about an hour before giving up.