She doesn't really think it'll be dangerous. Harrison Wells - the other Harrison Wells, from something called earth-2, says it's going to be fine, that no one besides Barry will be affected. And Laurel believes him.
(That, and she doesn't really want to be alone right now and needs people around her who she can call her friends.)
But something goes wrong, and she's knocked off her feet with the force of the dark matter. She feels her throat constricting and finds it suddenly impossible to breathe, and she gasps, sure she is going to die all over again.
And then everything goes black.
When she comes to she's surrounded by Team Flash, and they fill her in on what happened while she was out - that Barry went into something called the Speedforce, but that he's fine now, and he has his powers back, and Jesse and Wally were hit too and Wally's fine and Jesse's just come out of a coma. Laurel barely takes any of this in, still quite disoriented, and when she blinks she realises it's not just Team Flash crowding her bedside. She blinks again, and Nyssa al Ghul comes into focus, watching her anxiously, not saying a word.
"Nyssa..."
"I am so glad you are all right," Nyssa says. She hesitates, then. "I - should go."
"No, don't go," Laurel says, and it comes out as a plea.
"I am just here to check on your safety. I very much doubt anyone is comfortable with my being here."
"I don't mind," Cisco says immediately, and Laurel looks at him gratefully.
"Regardless, there is no reason for me to stay any longer." And before Laurel can even try to get up, Nyssa leaves.
"Don't move too much," Cisco says quickly when Laurel tries to sit up a bit straighter. "We still don't know how the particle accelerator affected you -"
"It hasn't affected me," Laurel interrupts. "I'm fine. I feel a bit dizzy, but that's it."
"We're still going to do some tests on you," Barry says firmly.
"Fine," Laurel says, sighing resignedly, and she holds out her arm so that Henry Allen, Barry's father, can take her blood.
They don't find anything. Barry tells her to watch out, though, because metahuman powers can take time to manifest.
She goes on patrol as Black Canary that night, but when she gets in a tussle with an arms dealer things go south quickly when her Canary Cry seems to be malfunctioning and she just screams emptily, to her dismay. The dealer has his machine gun aimed at her, ready to fire, when from somewhere above an arrow goes right through his chest and he falls forwards, dead.
Laurel manages to get up, and she knocks out a thug on her right while her saviour fires a flechette into the shoulder of the one on her left. The last of them down, Nyssa jumps down gracefully, pulling the scarf away from her face as she does so.
"Are you all right?" she asks.
"Yeah," Laurel says breathlessly. "I - how did you know I was here?"
"I heard about the arms deal and thought you would come here," Nyssa says, adding sternly, "alone."
"And is that the only reason you're here? Guns?" There's a sharp edge to Laurel's voice as she speaks, and this does not go unnoticed by Nyssa.
"I am sorry for leaving earlier. In truth… I was not sure you wanted me there."
"I'm sorry too," Laurel says, and at the sound of sirens approaching she puts her arm around Nyssa's waist as Nyssa aims an arrow at the top of a building. The two of them shoot up the zipline together, and when they reach the roof of Jitters Laurel immediately lets go, shaking a little with the adrenaline of it all.
"For what?" Nyssa says, and Laurel raises her eyebrows. "You said you were sorry. For what?"
"For… ending things the way that I did. For running."
"It is quite all right," Nyssa says, but it's clear she's lying.
"No, it's not," Laurel says. "I left. We didn't talk, work through things, like you're supposed to when you love someone. And for that I'm sorry. I just… needed some time to think."
"And what are you thinking about now?" Nyssa asks softly.
"Just… how much you mean to me. Someone reminded me of that, just before the particle accelerator exploded. And I figured - life's too short."
"That it is," Nyssa agrees, and before Laurel can say anything else Nyssa's kissing her, softly at first, then hard and fast with the kind of desperation and hunger that Laurel's missed. Laurel takes a step back, not realising she's standing right on the edge, and she tumbles off the building with a scream.
Only when she does, her scream seems to ripple through the air, shattering the window panes, and she hangs suspended in mid air, a few feet above the ground, for who knows how long, until finally she falls to the ground in a heap just outside Jitters. Iris comes running out, grabbing Laurel's hand and helping her to her feet while calling Barry. He arrives in a flash, speeding her away to Star Labs.
Once they're there they run more tests on Laurel.
"See that?" Cisco says, pointing at the computer screen.
"I do," Laurel says, "but I don't understand any of it."
"She's a lawyer, not a scientist," says Iris.
"That's your genes mutating. Into the metahuman gene."
"I'm… a metahuman?" Laurel says.
"You had your choker on when the particle accelerator exploded, right?" Cisco asks.
"Yeah, but that doesn't mean -"
"How can you explain falling from a twenty-storey building unharmed, then?" a voice from behind her says. Laurel looks up, sees Nyssa, tries to smile but doesn't quite manage it.
"I'm glad you're here," Laurel says instead.
"The cry must have cushioned your fall," Cisco explains. "It made a dent in the concrete, actually. But yeah, that's the only way to explain it, really."
"So, what, that means…"
"You're a metahuman now, yeah."