Chapter 1

Ava's POV

I make my way to Alex's lab, clutching my phone and mentally rehearsing what I want to say about this weekend's plans. Friday evening in the Stanford chemistry building feels different when most students have already escaped for the weekend.

Mom and Dad are flying back from their business trip tomorrow, and we should probably coordinate dinner arrangements. It's the kind of mundane sibling conversation we've had a hundred times before, but lately, even these simple interactions feel strained.

I push open the lab door to find Alex hunched over some complex apparatus, completely absorbed in his work. The familiar sight of him in his element, safety goggles pushed up on his forehead, lab coat slightly wrinkled, fingers delicately adjusting some microscopic component, makes me pause. He's so gorgeous.

"Alex?" I call softly, not wanting to startle him during what looks like a delicate procedure.

He holds up one finger without looking away from his experiment. "Give me two minutes, Ava. I'm at a critical step."

I settle into the small seating area he's set up in the corner, a couple of chairs and a coffee table that's usually covered with chemistry journals and half-empty coffee cups. Today it's relatively clean, which probably means he's been pulling another all-nighter.

Chloe should be free tonight for Netflix, I think, pulling out my phone to send my roommate a message. My finger swipes across the screen, looking for her contact, when something goes wrong. The phone slips slightly in my hand, and before I can stop it, I've accidentally tapped on Alex's chat thread instead.

"Oh shit!" The words slip out before I can stop them.

My autocorrect has somehow turned my intended "Want to binge-watch something tonight?" into "Want to spend the night together?" The message is already delivered, the blue checkmark mocking me from the screen.

This is a disaster!!! My face burns with embarrassment as I stare at the incriminating message. Alex is going to think I'm some kind of creep hitting on my step-brother. The irony would be funny if it weren't so mortifying.

"Everything okay over there?" Alex calls without turning around.

"Yeah, Yeah," I manage, trying to keep my voice steady while internally panicking about how to explain this mess.

"I'm going to wash my hands, be right back," Alex announces, finally stepping away from his experiment.

The moment he disappears around the corner, I'm on my feet. His phone is sitting right there on his desk, and I know from previous observations that Alex never bothers with lock screens. Too much faith in humanity, I used to tease him, but right now I'm grateful for his trusting nature.

Just delete the message and pretend it never happened. My hands shake slightly as I pick up his phone. The screen lights up immediately, showing our conversation thread at the top of his messages.

But something stops me cold.

The sender name isn't "Ava." It's "Phenylethylamine."

Phenylethylamine.

My chemistry knowledge is admittedly limited compared to Alex's, but I know enough to recognize this compound. It's the "love molecule". The neurotransmitter associated with the euphoria of falling in love.

What the hell?

My mind races as I stare at the screen. Alex has been calling me phenylethylamine in his phone. The implications hit me, turning everything I thought I knew about our relationship upside down.

For three years, I've watched Alex treat me with what I interpreted as polite indifference. He's helpful when I need something, pleasant in our conversations, but always maintaining a careful distance.

I convinced myself it was because I wasn't his type, or maybe because he saw me as just another Stanford student unworthy of his attention. I've spent countless nights wondering why Alex, seemed so determined to keep me at arm's length.

But phenylethylamine? That's not the contact name you give someone you're indifferent to.

Does this mean...? The thought is too big, too overwhelming to fully process. Has Alex been...?

Footsteps echo in the hallway outside, and panic shoots through me. I quickly place the phone back exactly where I found it, my heart hammering against my ribs as Alex reappears in the doorway.

"Sorry about that," Alex says, drying his hands on a paper towel. His eyes immediately go to his desk, then to me, and I can see the exact moment he notices his phone is in a slightly different position.

He picks it up, and I watch his expression change as he sees the message thread open on our conversation. His brow furrows as he reads the accidental text, and something complex flickers across his face.

"Ava," he says carefully, "did you touch my phone?"

My throat feels dry. "I... yes. I'm so sorry, Alex! I was trying to delete that message because it wasn't supposed to go to you and I just wanted to fix it before you saw it and—"

"What do you mean it wasn't supposed to go to me?" His voice is quiet, but there's something underneath it I can't identify.

This is it. The moment where I could tell him the truth, that it was an accident, that I saw his contact name for me, that everything I thought I knew has just been shattered. But the words stick in my throat. What if I misunderstood? What if phenylethylamine means something else entirely? What if I'm reading into something that isn't there?

"I meant to send it to someone else," I hear myself saying. "Someone I... someone I have feelings for."

Alex goes very still.

"Oh," he says after a long moment, and his voice sounds different. Hollow. "I see."

No, you don't see. The words scream in my head, but I can't make myself say them out loud.

"I should probably get going," I say quickly, desperate to escape before I make this situation any worse. "I just remembered I have... things to do."

"Right." Alex sets his phone down and turns back to his experiment, but I can see the tension in his shoulders. "We can talk about the weekend plans later."

I practically flee from the lab. The cool air hits my face as I burst through the building's doors, but it does nothing to clear the chaos in my head.

Phenylethylamine.

The word keeps repeating like a broken record. I stop walking and lean against a lamppost, looking back up at the chemistry building. Alex's lab window is still lit, a warm square of yellow in the growing darkness.

What if he really...? I can't even finish the thought. The possibility is too enormous, too life-changing to fully accept.

My phone buzzes with a text from Chloe: "Movie night at mine! Bring snacks!"

For a moment, I consider going. Losing myself in mindless entertainment and pretending tonight never happened. But I know I won't be able to focus on anything except that contact name and what it might mean.

I look up at his window one more time. The light is still on, and I can make out his silhouette moving around the lab. Tomorrow our parents will be back, and we'll slip back into our usual family dynamic. But everything feels different now, charged with possibilities I'm not sure I'm brave enough to explore.

If Alex really does have feelings for me, then what did that comment from three years ago even mean? That was when I started keeping my distance from him. Maybe I should start thinking from five years ago when we first met.