“Let me guess,” Jess said, “you’re the meetings guy.”

He smiled, nodding. “Endless investor meetings.”

“Send the hot scientist in, right?” she said, and immediately wanted to swallow her fist.

He laughed down at his tray of supplies, motioned for her to sit, and holy crap, it was suddenly seven hundred degrees in the lab.

“Could you—?” River gestured for her to roll up her left sleeve.

“Right. Sorry.” Awkwardly, she pushed it up and over her biceps. Very gently, but with absolute calm, River cupped a hand beneath her elbow, shifting her arm forward, and ran his thumb over the crease, looking clinically at the landscape of her veins. Much less clinically, Jess—covered in goose bumps from his hand on her inner elbow—stared at his eyes. They were, frankly, absurd.

She found herself leaning forward, slightly fascinated, and wishing he would look up again. “You have really pretty eyes,” she said, and sucked in a breath. She hadn’t meant to say that out loud. She cleared her throat. “Sorry. I bet you get that a lot.”

He hummed.

“And why do guys always get the thick lashes?” she asked. “They literally don’t care about them.”

The corner of his mouth pinched in with the suggestion of another smile. “A painful truth.” Satisfied with the vein situation, he reached for the tourniquet, tying the band around her upper arm. “I’m going to let you in on a secret, though,” he said conspiratorially, flicking his eyes up to hers and then back down. “I’d honestly rather be punched in the jaw than get one of those fuckers in my eye.”

An unexpected laugh burst free of her throat. River’s gaze returned to hers, lingering now, and her insides rolled over. He was so good-looking it made her mad.

Some of this must have shown in her expression, because his answering smile faded and he returned his attention to her arm, tearing open two alcohol prep pads and carefully swabbing.

His voice was a gentle rumble: “Make a fist.”

Is this a horrible idea?

He reached for the needle, uncapping it with a practiced tug of thumb and forefinger. Yes, this was a horrible idea.

Jess needed a distraction.

“What’s the story?” she asked.

“The story?” Focused, River leaned closer, and inserted the needle so deftly that she barely felt the pinch.

“Your story.” She cleared her throat, looking away from the needle in her arm. “The origin story.”

He straightened as the first vial filled. “About this?”

“Yeah.”

“Lisa didn’t go over the early studies in the presentation?” His frown down at her arm felt like professional concern, the beginning of a chastisement he’d deliver to Lisa later.

“She did. About your study on attraction,” Jess said quickly, and definitely didn’t watch his throat move as he swallowed. “And, um, long-term marital happiness. But I’m more curious about how you got there, what gave you the idea in the first place.”

He detached the first vial and screwed on the cap with a practiced press of a thumb, simultaneously securing the new vial in place with his left hand. These displays of dexterity were very sexually distracting.

“You mean, how an asshole like me started studying love in the first place?”

“I’m not sure if you’re trying to make me feel bad, but let me remind you: This is the room where you told your friend that I was ‘average.’”

He rolled his eyes playfully. “I didn’t expect you to hear that.”

“Oh. In that case, it’s not insulting at all.”

“You …” He drew his eyes up, over her chest, her neck, briefly to her face, and back down to her arm. “You’re a perfect test subject. From a scientific standpoint, average isn’t an insult. You’re exactly what we look for.” She wasn’t sure, but in the dim light, the tips of his ears seemed to redden. He switched out the second vial and easily fastened a third, releasing the tourniquet. “Anyway, that morning was busy.” He smiled to himself before adding, “And I was probably turned off by your attitude.”

“Oh my God.”

River laughed quietly. “Come on. I’m teasing. It’s obvious neither of us liked the other at first.”

“You didn’t like when I stopped you at Twiggs.”

“It startled me,” he said, not meeting her eyes. He cleared his throat. “I get deep in my head sometimes. You may have noticed that I can be a bit …” He unleashed the smile again, but only briefly. There and then gone. “Intense.”

“I’ve spotted the trait once or twice.”

Deftly, he unscrewed the last vial. “So: origin story. While I was in graduate school, there was a woman in David’s lab named Rhea.”

A woman, Jess thought. Of course.

“We were rivals, in a way.”

The way he added the last three words to the sentence clearly communicated Rivals who also fucked.

River pulled the needle out and immediately covered the puncture site with a square of gauze. He held it there firmly with his thumb, the rest of his hand lightly curled around her arm. “One night, at a party at someone’s house,” he said, “we started talking about the Human Genome Project from the nineties.”

“As you do at a party.”

He laughed, and the full, genuine sound delivered an erotic shock like a spanking. “Yes. As you do. We were talking about the implications of knowing every gene, the way that information could be manipulated. Could you, for example, screen people for certain jobs based on their genetic profile?”

“How very Brave New World.”

“Right?” He checked beneath the gauze to see if she was bleeding and, satisfied, reached for a fresh square, fastening it to her arm with some medical tape. “Anyway, I guess the drinks flowed and eventually I brought up whether it was possible to identify sexual attraction through DNA. Rhea laughed and said it was the stupidest thing she’d ever heard.”

Jess stared at him, waiting for the rest of it, and the heated effect of his laugh slowly faded. “That’s it?”

“I mean, that’s not it it,” he said, grinning shyly. “It turned into a real scientific undertaking, but if you’re wondering whether the project was sparked in a moment when a woman mocked me, you wouldn’t be entirely wrong. But it isn’t supervillain levels of insecurity or vanity; it was a genuine curiosity at first. Like a bet. Why did she think it would be possible to profile someone for an engineering job versus a graphic design position, but not for relationships? Aren’t both ultimately about suitedness and gratification?”

He had a point.

His face tipped down, he laughed quietly as he checked the labels. “Anyway, Rhea wasn’t the last person to mock the idea.”

“What does that mean?”

“Imagine being a fairly well-respected young geneticist and word gets out that you’re planning to use your expertise to find who’ll fall in love with whom.”

“People were dicks about it?”

He tilted his head side to side, a yes-no. “Scientists are often pretty critical of other scientists and what we choose to do with our time and knowledge.”