“Right,” Thora says slowly. “So the only reason we climbed this tower was because God wanted us to?”

Santi stays irritatingly serene. “That’s not how it works. He didn’t make us do it directly. He made us the kind of people who would choose to climb a ruined tower just to see the stars.”

Thora pushes her hair back. “Where to even start. What made me the kind of person I am?” She frowns at the echo of her thought as she left the club. “Maybe there’s something genetic there. God knows my parents are weird. But it also has a lot to do with my childhood, with the things I’ve experienced in my life.” The buzz of the argument makes her feel drunk, even though she only had one glass of wine and that was an hour ago. “Think about it. What if your parents had moved to Cologne before you were born? If you’d grown up here? What if mine had stayed in the Netherlands where they met? What if—I don’t know, something tragic had happened when we were children? We’d be completely different people.”

Santi shakes his head. “I don’t accept that. We are who we are. We would be the same people whatever happened to us.”

“Okay. Let’s do a thought experiment. Tonight, did you make a series of decisions that led to you lying on the grass and staring at the stars?”

He hesitates. “It felt like I did,” he concedes. “But I made those decisions because of the person I am.”

“And you weren’t even close to deciding something else?” She’s animated now, turned toward him, the city and the stars forgotten. “I can tell you I was. I nearly went down to the river. I nearly went back into the club, God help me. And if I had done either of those things, we wouldn’t be having this conversation.”

He grins. “So you think this conversation will radically change who we are?”

“Stop twisting my argument!” She’s angry at him, his security in who he is, when she feels like a bundle of contradictory ideas clumsily woven into a person. “No, maybe not this conversation. But if we—see each other again, become part of each other’s lives—”

His grin intensifies. “You want to become part of my life? Thora, I don’t even know you!”

She hits him on the shoulder. “Friends change each other’s lives all the time.” She rolls up her sleeve to reveal the tattoo she got two days ago in the Belgian Quarter, the skin of her wrist still reddened around a cluster of faint stars. “Take this. My friend Lily said we should get tattoos to commemorate starting uni. So if I hadn’t met Lily ten years ago, I would literally be physically different right now.”

Santi takes her arm, turns it to the light. “What is it?”