At Friendly’s, we ordered grilled cheese sandwiches, french fries, and sundaes, but sitting in a booth with Lucas across from me, his forearms resting on the table as if he didn’t want to miss a single thing I thought or said, I lost the ability to eat. Instead, I laughed.

I laughed when the waitress came over and Lucas confessed breathlessly that he was hoping she’d let him order off the kiddie menu because he wanted the toy and—blushing—she said okay.

I laughed when he told me a story about how last year the chemistry teacher left the room and this hockey player named Nunchuck had started mixing chemicals until something exploded.

We talked about TV. Seinfeld. Friends. The Simpsons. We talked about kids we knew at school. About Rosemary. He shook his head. “She scares me.”

I laughed. Outraged, but enjoying it.

“No offense,” Lucas said.

“No offense?” We were both laughing now. “She’s my best friend!”

“I’m sure she’s a good person.” He could barely get the words out, he was laughing so hard.

After eating his grilled cheese and both our fries, Lucas polished off his sundae, then mine, then pulled a handful of grubby, wrinkled fives and ones from his pocket to pay the check. I pulled out my wallet too, but he said, “No way are you paying. I ate all the food.”

“You didn’t eat my grilled cheese.” We looked at the desultory sandwich with one bite taken out, congealed and lonely on the tan plastic plate, its only friend a single crinkle-cut bread-and-butter pickle. And we laughed some more, as if we both understood at the same exact minute how pathetic it would be to fight over paying for something so forlorn and nasty.

Then Lucas stopped laughing. “Juliet,” he said, his voice suddenly husky, cracking on the third syllable of my name in a way that worried me. I smoothed a lock of hair down across my forehead and pulled my wallet back toward me. I knew what he wanted to talk about.

“I don’t understand the things you’ve been saying,” I said, hoping to be preemptive.

Lucas looked straight into my eyes and sighed in a comforting, aw-shucks kind of way. “I don’t get them either,” he started to explain. “But here’s the thing. I guess—” He stopped, thought, started again. “I remember—” Another stop. He laid his hands palms down on the tabletop as if to signal he meant business, but he continued to say nothing at all.

“You … remember?” I prompted. He smiled a crooked smile. I couldn’t help but smile back. He turned his hands over, cupped, as if waiting for them to fill with rain.

“That first day in physics, when you walked into the room and caught me looking at you?” I nodded. “The moment I saw you, I remembered. I’d seen you before.” He took a deep breath. “And I probably shouldn’t even be telling you about it, but part of what I remembered makes me think I can trust you.” He was looking straight at me still, those big blue eyes. If I were our waitress, I would have let him order off the kiddie menu too.

“You can trust me,” I said.

“Well, seeing you, I just knew I’d seen you in that exact spot, in that exact room. I knew you were going to sit at that desk. I knew you would turn around to see who else was in the room. I knew you were going to end up looking at me.”

I swallowed. I felt like I was standing on a dark stage and suddenly someone had turned on a spotlight. “You remembered this?”

“I thought it might just be déjà vu. But it wasn’t. Déjà vu fades. An hour later, the memory is gone. But this one stayed strong.”

I laughed, as if laughing might turn this whole idea into a joke. He laughed a little too, but it was a running-out-of-gas-on-your-way-to-get-your-flat-tire-fixed kind of laugh.

I looked down at the white Formica tabletop sprinkled with flecks of gold. I didn’t know if I thought he was crazy or if I felt flattered that he trusted me. What Lucas was saying didn’t feel real. But Lucas did.

“I remembered being with you on the roof,” he went on. “I remembered it so clearly I thought bringing you there, maybe, I don’t know—I thought maybe you’d remember it too. But you didn’t, right?”

I shook my head.

“And now I’m freaking you out?” he said.

I wanted to let him know it was all right, that I was okay, but I couldn’t. I was embarrassed, as if I were the one who had said something ridiculous. The lights in the restaurant felt brighter. The sounds of plates landing on tables and cutlery being shuffled in bins and soda fizzing when it hit a cup of crushed ice—I couldn’t think amid all this noise.

“I need to get out of here,” I said. I was already standing when Lucas tilted the grilled cheese plate in my direction.

“You’re sure?” He was trying to go back to the part of the dinner when we’d been joking.

I half laughed, half choked.

Once we were on the sidewalk, we started to walk, but it wasn’t the meandering kind of walk you might take after ice cream sundaes. I was walking fast, like I was trying to catch a bus, and Lucas was hurrying to keep up. He didn’t ask me what was going on. He just followed.

“Juliet?” he ventured after a while. We’d reached a wooded park near my house where people let their dogs chase squirrels. No one was around. “Can we slow down?”

I couldn’t. “Have you thought about seeing a doctor?” I asked.

“I don’t think it’s something a doctor’s going to be able to help me with.”

“Could you have hit your head, maybe? Playing hockey? You’re sure you don’t have headaches or anything like that?”

He stopped walking, and as if he was getting a headache right then, he pushed his hair off his forehead with his fingertips and held his temples between his palms.

“Does it hurt right now?”

“No,” he said. “Yes. A little. Stop.” He stopped walking. “Can we please stop walking?”

I noticed it was getting dark when Lucas stepped off the sidewalk and headed a dozen yards into the shade of the trees, his eyes fixed on the patchy grass as if he was looking for something he had dropped there. I followed.

“My mom’s a nurse,” he said, glancing up at me when I put a hand on his shoulder. “She happens to work in a neurology ward. I know all about traumatic brain injury, concussions. That’s not what this is.”

“Are you sure—” I began.

He interrupted me with a groan. “I’ve done a terrible job of explaining this to you.” He walked even deeper into the trees, and I followed. “But then again, how can I explain something I don’t even understand myself?” He took my hand and pulled me behind a tree. We couldn’t see the road now. “Juliet,” he said, his voice husky.

He smiled, and I felt myself wanting to smile at him. Stop it, I instructed myself. Be rational. I willed the muscles in my face to play dead. But my mouth was twitching. I knew that.

The moment my smile finally emerged, his exploded. We stood there for I don’t know how long, looking into each other’s eyes and grinning. All my embarrassment was gone. It was like that time on the front lawn of my house when he’d caught me watching him not being able to mow down that clump of grass near the fence.

He lifted my hand and looked at it, playing with my fingers.

“In physics, the second I realized I’d been in that room before, watching you come in, having you turn in your seat and look right at me, I also remembered being on the roof with you. It was like the two memories were attached to each other.”

“You really remember being with me on the gym roof?” I said. “You remember it like it happened?”

Letting go of my hand, he pressed his fingers into his temples. I was thinking, Brain tumor. A little giddy from all that smiling, I thought, It’s a shame his whole head is going to swell up, because, well, those cheekbones …

He started speaking again, slowly, as if he wanted to give me just the facts without any more interruptions.

“I was kind of hoping that when we went up on the roof, the memory would fade, that once I was up there with you for real, the difference between what I was imagining I remembered and what was real would become clear.”

“Did it?”

“Not at all, actually,” he said, like he was just realizing it. “It made me remember more. I remembered that the time before, it was dark out. We were up there at night. And I think you were wearing a dress.”

“What kind of dress?”

Lucas shrugged. “A dress dress?” He pointed to the space next to his thighs where a dress would hang if he were wearing one. “You looked nice.”

“You could have imagined it.”

Lucas’s eyes grew big with frustration. He looked like someone trying to come up with the answer to a math problem they don’t have the first idea how to solve.

“On the roof …,” he said. “Okay, fine, I’ll just tell you. What I remembered about being up there was that I was kissing you.” He stopped, as if waiting for me to yell at him. When I didn’t, he went on. “And I couldn’t have made up what it felt like. I couldn’t have imagined.”

I felt like suddenly all the oxygen had been removed from the atmosphere. I couldn’t breathe. I didn’t want to.

“Look, Juliet,” Lucas said. He took my hand and pulled me toward him, wrapping an arm around my back. Despite the craziness of what he was saying, his arm was strong and steady. He was looking at me like he was going to find the answers in my eyes, and I let him look. I looked back. His eyelashes were a darker shade of blond than his hair. His skin was smooth below the stubble on his jaw.

He kissed me gently, and I felt my hands rising to touch his face. I closed my eyes, but when I opened them again, he was still looking at me the same way, as if he were searching for answers.

“What do you want from me?” I said.

“I don’t know. But I want something.”