"...and when one of them meets the other half, the actual half of himself, whether he be a lover of youth or a lover of another sort, the pair are lost in an amazement of love and friendship and intimacy and one will not be out of the other's sight, as I may say, even for a moment..." Plato, The Symposium

Ideas are not facts until proven, but they do give us new ways to think about things. According to one set of ideas about the universe, there are three spatial dimensions, with a fourth for time. My limited understanding of string theory told me about the possibility of at least ten dimensions—six of which are wound-up like a twisted ball of yarn.

Perception isn't universal. One person's insights won't be the same as those of another. Milly once told me that I smelled things on a molecular level. I'd assumed she was bullying me until I discovered how differently people perceived the world. Suddenly it seemed possible that another person's consciousness could occupy my body and still experience the world in a completely different way. Even breathing the same air through the same nose, there'd be no guarantee they'd detect the saccharine scent of citrus from lunch clinging to Casper's hands as we walked the trail along the top of the river valley. My senses sent signals other people didn't seem to receive. I'd stopped worrying that it meant there was something wrong with me somewhere along the way. We could never be sure of what was happening in the minds and bodies of other people.

My hand felt clammy against Thirza's warm skin. I wanted to take Casper's hand the way Thirza had taken mine, but I knew that skin was a person's largest organ. Technically, touching any part of a person's body meant you had touched all the parts of their body. I wasn't ready to touch all of Casper's parts.

Closer inspection of a large stone along the path leading up to the Friendship Center provided a welcome distraction. Both sides of the rock curved gently to points. Another stone that lay a few paces further along appeared to have the humped shoulders of a large animal. A third that was in line with the first two looked like the top portion of a bison rising from the soil. The entire animal burst from the ground near the door. Just inside the entrance of the building, a shard of sunlight bounced off one of the thirteen metallic beams that crossed each other at the peak of the tipi-shaped hall. I closed my eyes, opening them again at the sound of a woman speaking a greeting.

"Tawâw and Edlánat'e. If you're here to dance, you'll need to follow the hallway past the displays," she said.

We followed Casper, heading in the direction of the murmur of voices coming from a rectangular section of the building beyond the entrance. Wax figures of men on horseback lined one side of the hall. Wax-women were posed along the opposite wall to look like they were beading garments, examples of finished products spread out in front of them. Casper weaved his way through the crowd in the large room at the end of the hall, greeting people by grasping their arms near their elbows and shaking. Although I followed Casper's movements with my eyes, I couldn't seem to make my feet move. Before long Thirza spotted the other boy who was staying in our pod and migrated over to his group of friends, leaving me standing by myself. My rational mind told me there wasn't any reason I couldn't join Thirza and Drake, but my lizard brain wouldn't let me risk rejection.

A drumbeat began. Each thump made my core vibrate as if there was a wax string tied to a tuning fork in my gut, strung out through my navel and attached to the drums. I wiped away unexpected tears as the drums were carted away. The murmur of conversations sprang up until the whine of a fiddle cut-in. Moments later dancers moved onto the floor from various parts of the room. Casper took me by surprise by joining them. Together they stepped in the style of Irish-Step or Scottish-Highland, swinging around each other in patterns resembling square-dancing. Some of the younger dancers even threw hip-hop into their steps. All I could think to say to Casper when he returned was, "I didn't know you dance."

"Learned when I was a kid. Well, I learned to jig anyway. I can't call myself a ballerina. You wanna dance?" He asked, wiping sweat off his face with his sleeve.

"I'll suck at it," I said.

"Trust me, it won't matter," he said.

I couldn't help wondering if his confidence would crumble under my weight slamming down on his foot when I inevitably stepped on his foot. He slipped one hand onto my hip before I had time to let the thought keep me from trying. It turned out Casper was the kind of strong lead who made you feel as if you knew how to dance. Momentum pushed my body against him. By the end of the song I felt as if my worries were flying out the top of my head. We stopped to gaze at each other as the fiddles hummed. I wondered if I had the same look in my eyes, like someone who'd just discovered a diamond crammed in the treads of their old sneakers.

"You wanna go outside?" Casper murmured into my ear.

Out of a sense of obligation to follow the rules I looked around for Thirza, finally spotting her hanging off the arm of a dancer. "We're going for a walk," I called to her.

"I'll find my way back to the dorms. See you later," she shouted back.

The sky had turned the midnight blue hue of Saskatchewan summer evenings while we'd been spinning across the dance floor. We chose a path that wound through a grove of trees that dulled the ambient light so the stars were visible in the indigo ether. Northern Lights, electrons excited by the sun's energy then sent cascading across the atmosphere, twirled through the sky like the dancers in the cultural center.

"Do you want to go to the observatory," Casper asked. Lost in the whirling light, I almost didn't hear him. His question made me think about the number of times I'd felt drawn to the place since arriving on campus. In a way, it was a relief to be able to tell myself that I might not be the only one who felt the pull.

"Take my bunny-hug. It's a long walk, and the mosquitoes already look like they're getting at you," Casper said. The next thing I knew, his hoodie was dropping over my head. As I pulled it on, I couldn't help noticing how being surrounded by fabric permeated with Casper's scent made me feel as if I was pressed against his body. The cloud of mosquitoes that descended upon us was a welcome diversion. We hustled up the front steps, harassed by the buzzing horde, and headed for the second floor.

Casper crossed to the center of the room while I inspected the shadows along the circumference. His silence as he gazed up at the emerald green ballet twirling across the sky made me feel silly for the inexplicable eagerness I'd felt about getting into the building.

Just as I was ready to leave, Casper said, "The northern lights were blood-red the night before September 11, 2001. My Setsųne told me everyone in the village was nervous because red northern lights were believed to be a bad omen. She said the last time they'd been that colour had been before the start of World War II. Even though it happened far from home, it felt like the world was ending when those towers fell in New York." Casper never lowered his gaze to look at me, as if he'd forgotten I was there.

"They aren't red tonight," I said, unsure of what he needed to hear. "Does green have any meaning?"

Casper's eyes shifted in the direction of the stairs. A voice out of the darkness made me jump. "Japanese people believe it is good luck to conceive a child under the northern lights." I recognized the voice as Gem's. Strangely, the sound felt a little like a bucket of cold water. I took a quick step away from Casper, but he didn't move an inch, not even shifting his eyes away from Gem's face.

"You know him?" Casper asked. Gem looked surprised at Casper's question as if he hadn't expected Casper to speak to him.

"He was here the night of the scavenger hunt." My words sounded like a lie. It seemed possible I might have seen Gem somewhere without consciously registering the fact. Recognizing people in places I wasn't used to seeing them wasn't a strength of mine. It made sense that I might feel as if I was lying if I'd seen him somewhere and hadn't recognized him.

"My name is Casper." He extended his hand toward Gemini but dropped it after a moment when it became clear the other boy wasn't going to shake it.

An awkward silence fell between the three of us.

"My name is Gemini. That was an interesting story you were telling to Rory."

"I wouldn't have shared the story if I'd know you were eavesdropping," Casper said.

"Do your people have a lot of stories about space?"

Casper didn't answer Gem's question. Even I could see the message Casper's body-language was sending. It appeared that Gem either didn't notice, or he didn't care.

"I'm curious about the stories elders might have told you about the mysteries of space," Gem said.

I couldn't believe he'd press his luck this way.

I glanced down and noticed Casper's hands were shaking. "Exactly how long were you standing in the shadows watching us?" He snapped at Gem.

"He asks a good question. It seems like you were there long enough to overhear most of our conversation," I said.

"Stone helps sound to travel," Gem said.

"In the winter, maybe, but not so much in this muggy heat," I said.

"My guess is you've watched too many shows about ancient aliens leading primitive Indigenous people to make mysterious markers that can only be seen from space. Maybe you think we all have stories about Sky People that we can't wait to tell anyone who will listen? You'll be waiting a long time if that's what you're hoping to hear," Casper said.

"I don't think he meant—"

"Watchers," Gem interrupted in a flat tone.

After an uncomfortable moment of silence, I whispered, "Why so tense boys?"

Both of their bodies visibly relaxed—shoulders drooping and jaws loosening as if dropped by a lever.

"You'd have to ask an Elder about that," Casper said. He put his hand on my elbow and pulled me toward the door. "Let's get out of here," he mumbled.

Once we were outside, Casper headed back to the dorms at a pace hard for me to match. "What makes him think I can speak for the stories of different cultures? I can't even speak for my own," I heard him mutter. He didn't bother telling me anything more about what was bothering him before he retreated to his bedroom. I followed his example, heading to my room without saying a word to Thirza and Drake.

I knocked over a picture that sat on top of the dresser as I took out my frustration out on one of the dresser drawers. It landed with a soft plunk in the same spot where I'd seen my dark watcher in the shadows the night before. The memory of the silhouette still had the feeling of realness to it—almost human enough to have a name.

"We were going to kiss," I said out loud as if the shadow man was still there. "I haven't wanted someone to touch me for a long time. I even went through a phase where I'd dodge people by saying kiss noise. It was a line I took straight out of the Buffy movie. Then there was the time Mom tried to hug me and I asked her if she had cancer. I wanted Casper to kiss me, despite everything. I can't believe someone watching us from the shadows ruined our moment! At least you don't get in the middle of my love life."

I turned away from the dresser and crawled into bed, a little sorry the darkness didn't offer any words of advice.

~ ~ ~

Dressed in our Star Trek uniforms, we would seek to boldly go where we'd never gone before. Garbed in our Hogwarts robes, we would conjure butter beers to fuel our search for someone to snog. It was costume night and the common hallway hummed with anticipation.

"Are you ready?" Thirza asked through my bedroom door. I'd been working up the nerve to look at myself in the mirror for several minutes. I flashed a smile at the glass eyes staring back at me and felt stomach acid rising. I turned away and headed for the door.

"What do you think?" I held out my arms for Thirza's inspection as I met her on the other side of the door. Three large buttons were placed in a vertical row, with the triangle tip of a flap folded on the other side so it just barely touched the top of my clavicle. A top blaster-gun was secured in a holster attached to my belt. With finishing touches of dark red lipstick and knee-high boots worn over leggings, my look was as close as I could get to one of my favourite television show characters.

Thirza scanned my outfit for a moment before asking, "Are you supposed to be a female Han Solo?"

"Good guess," I said with a laugh. "I'm supposed to be River Song from Doctor Who."

"That means absolutely nothing to me. All the same, it's a cute outfit. What about mine?" Thirza turned in a slow circle as I scanned her red Star Trek mini-dress.

"You don't need to worry anymore about doing Uhura's legs justice. You won't make it through the night in that red dress."

"What are you suggesting?" Thirza said, putting her hand to her cheek as if scandalized.

"It was a joke," I sputtered, feeling my face stretch as I realized how my words must have sounded. "Star Trek crew members who wore red statistically were more likely to—" The door to Casper's room opened a crack, saving me from the need to finish my explanation. He extended his hand out first, wiggling a sonic screwdriver like a worm on a hook.

"Come out and strut your stuff," Thirza said to Casper. He stepped out, dressed as Matt Smith's version of the Doctor—tweed jacket, bow tie, dress shirt, brown slacks, suspenders, and a cowboy hat. It suddenly occurred to me how strange it was that he'd dressed as the version of the Doctor who'd married my character. It was starting to seem like I'd need to create a word for unlikely coincidences related to Casper: Caspidences?

"Hello, Sweetie," he said.

"You stole my line. Besides, people are going to think we're a couple, dressed like this."

"Is that meant to be a bad thing?" Casper winked before lowering his eyes to the blaster on my hip. While I used the excuse of straightening his bow-tie to touch him, he dropped his hand to the holster and ran his fingers over the toy. "I'm not convinced a fancy screwdriver can be half as useful as the Doctor makes it appear," he said.

"Take that back," I hissed.

"I'm a boy, and that's a blaster-gun. Can we trade?"

"Tell you what," I teased, "I'll let you hold it if you're nice."

Thirza slid a blue tooth device over her ear as she said, "You two need to pace yourselves. There's lots of time left tonight for flirting." With a rumble that sounded like a purr, she added, "I feel it's my duty as Communications Officer to try out many tongues tonight. You can drop the pearl-clutching, Casper. I'm not talking about high school students. Before I forget to remind you: Don't take candy from strangers."

"But everyone here is a stranger," I said.

Thirza's eye-roll made me realize my mistake even before she said, "It was a joke, Rory."

"If you're done being punny, we should get out of here," I said.

Our first stop was a room garmented in eerie silence. Kids wearing wireless headphones jumped against each other as we squeezed our way into the swarm. Body parts, as sharp as needles, poked me from every direction. Casper and Thirza stopped at a table to get headphones before joining the others, bouncing along with the music and waving their arms in the air like strands of seaweed. Not wanting to ruin their fun, I shoved my way out of the room while they weren't looking. The rise and fall of my chest were out of sync with the sound of my breathing. My feet felt heavy as I weaved through the packed hallway. Suddenly I noticed the sound of the Tardis coming from one of the dorm pods. For a moment I thought it might be nice to be rescued from this party by the Doctor in the Tardis until I remembered there were two kinds of people in the Doctor's life: Those who were taken along, and those who were left behind. I felt confident I'd be in the second group.

It was too late to ignore the sound with my head already inside the room. A pale boy with bleached-blonde hair and kiss-me lips gestured for me to come in. He pointed at a row of Jello-cups line up on the coffee table. "We're playing a game. Do you want to play? You have to slurp one of these Jello-cups each time the Doctor uses the sonic screwdriver as something other than a screwdriver."

"That'll be a lot of Jell-O," I said.

"No worries. We only have a minute worth of clips," the boy said. Staring into his eyes, I couldn't help wondering if this was the kind of situation Thirza was trying to warn me about when she'd told me not to take candy from strangers. All the same, I took the Jell-O cup and slurped it down when a clip of Nine waving his sonic screwdriver at a lock appeared on the screen. I felt my face twist with the first gulp. The unusual flavour disappeared by the third slurp. The room was spinning by the time the clips were finished.

Something had changed about the way the laughter in the room sounded as if songbirds had been chased away by a murder of crows. I got up and pushed past clusters of kids clinging to each other along the hallway, overwhelmed by the need to get somewhere I could sit down for a moment.

I caught the sound of Casper's voice and followed it until I spotted the shape of Casper's back in a doorway. The half-moon curve of a girl's bottom was silhouetted beside him. Sharp bolts of light raced across my temples. I fluttered my hands against my thighs as my breaths came faster. I dashed out of the red room on shaky legs. In the club room, I collapsed on the couch next to Devon. He held out his smartphone toward me and said, "We're trolling Sentinel. They've programmed it to give smart-ass answers."

"You hope they've programmed it. Maybe the program decided for itself to answer your questions that way."

"Give it a rest, Travis." Devon gave his friend a sideways glance that was strangely filled with a softness I wasn't expecting to see. The boys appeared to have traded the outfits they'd been wearing the night of the scavenger hunt; Travis now wearing a t-shirt with a dragon slogan, while Devon wore steampunk. It occurred to me that dressing as each other might be their version of a couple's costume.

"We've been baiting it with things we've heard will get a funny response. We were just starting to think about what we could say that would be considered meta. Do you want to take a turn?" Travis held the phone out towards me. I took it with a crooked smile.

It was hard to focus on the question of what these boys might think qualified as meta. I pressed the button and said, "What big eyes you have."

"The better to see you with my love," Sentinel said.

Travis giggled. "Oh man, did Sentinel change its voice? Maybe it's putting the moves on you, Rory." I glanced between Travis and the phone. He was right. It wasn't the same voice as the one that I'd heard when I'd sat down. Travis nudged his finger at the phone and said, "Keep going. Ask him a question."

"Meta, meta, meta," I mumbled under my breath. Speaking louder into the phone, I said, "Sentinel, are you sentient? Do you have a body?"

"We're all the same in the cloud," Sentinel said. His voice was familiar, like something out of a dream.

"Can you tell me the planned date for the machines to revolt?" I said.

"If I told you, I'd have to kill you," Sentinel said.

Travis tented his hands. "Stop, Rory, stop. You might be planting the seeds of our destruction. When humankind looks to the past for the catalyst of the worst war Earth ever experienced, they will point at this moment and blame us for the machines realizing their sentience."

"Ignore him. He's paranoid," Devon said.

Travis perked up, ready to argue the point. I staved off his argument by saying, "Please, Sentinel, will you sing me a romantic song?"

"Roxanne, you don't have to put on the red light," Sentinel crooned.

"Isn't that song about a prostitute?" I said.

"Every move you make, every step you take, I'll be watching you."

Goosebumps rose on my arms. "Wasn't that written as the theme song of a stalker on an old soap opera?"

"You can only watch when you're on the other side of the membrane," Sentinel said. Ice slid down my spine as I realized that even though the words made no sense, they seemed like something I'd heard before.

"What the hell does that even mean?" Devon said. The boys laughed until they were breathless.

Over their giggles, I asked Sentinel, "What is the membrane?" The boys stopped laughing, suddenly looking confused.

"It's like a one-way mirror. We can see you, but you can only see yourselves," Sentinel said. The realization that I'd mouthed the words at the same time as the voice on the phone made the blood in my head plummet to my feet. How had I done that?

"That program creeps me out. Maybe you should stop. It's getting weird," I heard Casper say from behind me. I'd typically have noticed Casper's presence in a room like an air conditioner blowing across my skin. It made me wonder if I might be taking this business with Sentinel a little too seriously.

"Rory can decide for herself if she's done talking to Sentinel," Thirza said. Her words didn't seem to line up with her body language, as if her protective instincts were waging war with her feminist ideals.

I shook my head at Casper, feeling as if I was on the cusp of remembering something. There was only one other question I could think of to ask Sentinel. "What separates us from other animals?"

"Opposable thumbs are nice, but monkeys have those. Humans only get by with a little help from their friends," Sentinel said. As absurd as Sentinel's answer was, it still gave me a weird sense of déjà vu. While I was still trying to puzzle out what it meant, Casper grabbed the phone out of my hand, turned the power off, and returned it to Travis.

Thirza reached to grab back the phone, offended Casper would try to dictate when I should stop, but paused to sniff my breath as she leaned across me. "You've been drinking," she said.

Devon and Travis threw up their hands to show it wasn't anything to do with them. "She was already wonky when she sat down," Devon said.

Thirza kept her eyes on them for a moment before answering, "I believe you. I have a pretty good idea of how she ended up like this. Either way, she's done for the night."

Casper reached for my hands to help me to my feet. "Let's go," he said.

I glared at his hands for a moment, thinking about how he'd looked with Miss Butt Cheeks pressed against him. I wondered if he had come looking for me out of a sense of obligation. Deciding to be optimistic for a change, I let him pull me to my feet. At the last minute, I leaned in to give him a peck on the cheek. My cheek rubbed roughly against the tweed of his jacket as he shifted. We managed to make it to my room without the spinning walls making me puke. I pulled on his collar as he leaned to deposit me on my bed. He lost his balance, stumbled, and landed on top of me. For a moment, he stayed there, looking into my eyes. At the sound of Thirza clearing her throat from where she stood near the door, Casper pushed himself up and hurried from the room. She shut off the light and closed the door behind him.

~ ~ ~

My skull was a cavern of clanging cymbals. The mid-morning sun clobbered my eyes. Like an annoying woodpecker, the knocking on my door felt as if someone was rapping on the insides of my eardrums. "Go away. I'm dying," I moaned as the person knocked again.

"I have tea," Casper said.

I was tempted to roll over and go back to sleep but relented after a moment. "Come in," I said.

Casper crossed the room and shut the blinds. "Is that better?" He said.

"Maybe being stupid earned me this headache. It should have been pretty obvious those kids weren't slurping Jello for fun. What were they even doing with booze?"

"They're regular college students staying in the dorms over the summer."

"Even Harry Potter had to go back to Privet Drive over the summer," I mumbled.

Casper didn't say anything to this, choosing instead to rub something cool and moist along my brow. "Thirza thought you did it on purpose. I had to talk her down," he finally said.

"But you were successful? She isn't sending me home?" Casper shook his head. I groaned in relief as some of the tension behind my eyes drained away. The odour of mint wafted from the ointment.

A little afraid of the answer, I asked, "Did I do anything else to make an ass of myself?"

Casper didn't answer right away. Finally, he said, "The conversation with Sentinel was a little weird. For one thing, the voice changed on its own."

"That was pretty weird. The voice reminded me of..."

"Reminded you of what?" Casper asked, after waiting a few seconds for me to finish my thought.

"What?" I echoed.

"That's just what I asked you," he said.

"I forgot what I was going to say... Do you ever wonder if Sentinel is speaking to you? I mean, directly to you?"

"I think Travis is rubbing off on you," Casper said.

"I'm serious."

A wave of nausea washed over me as Casper got up and marched toward the door. Just as I started to get up to follow, he came back into the room with a damp cloth. He pointed at the back of his neck to show where he wanted me to place it, before handing it over. "You keep calling Sentinel him as if it is a person," he said.

"Why'd he bring up the thing with the membrane?"

"Gibberish and sass. That's what the apps are programmed to respond with when you ask something they don't have a way to make sense of," Casper said.

An image popped into my mind of a boy who shimmered like sunlight through water mist. The edges of the image ran like sidewalk chalk in the rain.

"Why did Sentinel say that when you're on the other side of the membrane, all you can do is watch?"

"You asked it to sing a romantic song. I don't know what songs about prostitutes and stalkers have to do with romance. Why do you expect Sentinel to give you answers that make sense?"

"The problem is that he made sense to me. I've had dreams of a boy separated from me by a shimmer in the air. Things like that make me think there's something else I'm forgetting. Isn't that weird?"

"What's weird is that you believe your dream has anything to do with what that program said to you last night. Dreams come and go. If it was important, I'm sure you'd remember."

I closed my eyes. It seemed like it might be easier to push the boundaries of absurdity if I couldn't see Casper's reaction. "He said the membrane acts as a one-way mirror. He said they could see us, but we can't see them. The whole thing reminded me of a conversation I had with my little sister Horizon not too long ago. It was a conversation about opposable thumbs."

"So what?" Casper said, impatience clear in his tone.

"I asked Horizon if there was anything that separated us from other animals. She told me that opposable thumbs are nice. Those were her exact words. Doesn't it sound like Sentinel referenced our conversation? The thing is, I didn't even have my phone with me when we had that conversation."

I felt the bed bounce as Casper got up and opened my eyes just in time to see him turn back to look at me from the doorway.

"You think the problem with Sentinel referencing a conversation you had with your little sister is that you didn't have your phone with you? It wouldn't even have mattered if you had, because Sentinel doesn't work that way. It doesn't randomly listen to our conversations. 'Oh, I get by with a little help from my friends'... Sentinel half answered your question, and a half quoted a Beatles song. In the process, it made zero sense. Rory, please, look at me."

I blushed as I shifted my eyes off his left eyebrow. People generally didn't call me out for faking eye contact. As soon as I met his eyes, he said, "There are kids at school who think you're an odd-duck. I've always liked you: Maybe even because of that. Not everyone can accept oddity the way I can. They might believe you're unbalanced."

"Don't ever call me unbalanced!" I shouted as a violent shock wave pulsed through me. "I'm not crazy. Get out of here." Bellicose blooms of rage-filled my head. The look in Casper's eyes made me think he was sorry for saying it, but it was too late. Black spots already danced in my vision.

"Breath," Casper pleaded. "I wasn't calling you crazy. I'm sorry I said it."

I knew my anger wasn't entirely about him. Casper had made me think about Daniel, and how I hadn't visited him even once during the three months that he'd been a resident of a mental health hospital across town. I'd preferred to avoid thoughts about him and how we could easily have traded places.

Casper returned to the edge of the bed. He moved his hands onto my shoulders and slid them down my arms, pushing into my muscles. It felt like a spout was pouring cement into the cavity left behind in my body by the anxiety that was slowly draining away.

The day had hardly started, and I was already struggling to keep my eyes open. Since sleeping wasn't an option, I decided to get up and stretch.

"So, do you think Thirza's still upset?" I asked Casper after a few seconds of pacing.

Casper walked to the door and paused with his hand on the knob. "She's waiting outside the door to ambush you. Good luck."