Watt couldn’t take it anymore. He reached forward with rough hands and pulled Leda back, hard, so that her head snapped a little and that unearthly scream finally came to an end.

They stood looking at one another for a moment, he and Avery and the other girl. They had all seen what happened. Avery’s face was white, her shoulders shaking, and Watt realized she was silently crying, the moonlight turning her tears a shimmering silver. Of course, Eris had been Avery’s oldest friend. He wanted to fold her in his arms and hold her while she sobbed, but he didn’t move.

Leda was hunched over, trembling. Her eyes twitched under their closed lids, and her face was twisted in pain. God, was she still high from last night? Watt couldn’t believe that it was only yesterday that he’d been drinking whiskey with Derrick in the living room. Everything since then felt like a blur—Leda seducing him and drugging him, and him waking up only to rush up here, frantic with worry for Avery.

But Eris was the one he’d been too late to save.

The unfamiliar girl broke the silence. “We need to call the police,” she said, and her voice quavered only a little. Watt asked Nadia who she was, and Nadia cross-checked her features with the Tower’s master facial recognition. Rylin Myers, thirty-second floor. Watt wondered how she’d ended up here.

Avery blinked, dazed. “I’ll do it,” she said, but she was still crying. Watt couldn’t bear the sight of it. There was very little he could do to help right now, but at the very least he could give her the chance to grieve properly.

“Let me,” he said. Avery nodded gratefully.

It was as if the words were a spell, ripping Leda from whatever living nightmare she’d been trapped in. She straightened her back and lifted her head, her eyes blazing. “Oh no you won’t,” she said, frighteningly calm. “You don’t want to do that.”

“Leda, Eris is dead,” Avery said. “We have to get help!”

“No one can help her if she’s dead,” Leda pointed out ruthlessly.

“It’s your fault she died!” Avery screamed.

“Really?” Leda took a deep breath. The more the rest of them panicked, the more she seemed to be regaining a measure of calm. “As I seem to remember, you’re the one who brought us all up here.”

“You pushed her!”

“Did I?” In the wake of Avery’s shouting, Leda’s voice was low and quiet. “I don’t think I did. I think Eris had too much to drink, at your party.” She leveled her gaze at Avery again, her eyes unblinking, as if she were a Gorgon and could turn her friend to stone. “And then she slipped.”

Rylin chimed in. “I saw you push her. I’ll tell the police that’s what I saw.”

Leda glanced around, her eyes darting from person to person as if she were a cornered animal plotting a way out. Her mind seemed to be turning over various possibilities. “Rylin, right?” she said, turning to the lower-floor girl. “You’re the last person who should be going to the police right now, and you know why.”

Rylin hesitated, and in the silence Leda drew her shoulders up, gaining momentum. “None of you are going to the police until we have our story straight. Eris got drunk; she slipped and fell. If anyone says otherwise, then I can’t promise to protect your secrets.” She laughed wildly, a bright hard glitter in her eyes.

Watt bristled as he understood her meaning. She was trying to threaten him with his hacking. Screw that, he thought; he and Nadia were careful, too professional, to leave any kind of trace. “You think you can threaten me about my side jobs?” he snarled, not caring that Avery and the other girl heard. “You’ll never be able to prove it. You’ve got nothing on me.”

“Oh, Watt,” Leda said. Her voice lowered conspiratorially. “Like I said, I have so much worse on you. Don’t push me.”

He stared at her, confused.

“Sorry about the pill,” Leda added, in an almost cheerful tone. “But you forced my hand. If you’d been a little more fun, I wouldn’t have needed to resort to it.”

Avery glanced from Watt to Leda, struggling to keep up. Watt was livid. “I’m calling the police and telling them everything!” he exclaimed.

“As you wish,” Leda said, with a tight, mirthless smile. “Please put them on with me, afterward, so I can tell them who Nadia really is.”

Silence fell over the roof. Leda looked at Watt. Could she really know? he thought wildly. But how?

“Oh yes,” Leda said, following the direction of his thoughts. “I’m so eager to meet Nadia, you know. Unquantifiably eager.” She put just the slightest emphasis on quant, so slight that only he would hear it.

Watt felt sick. He was powerless to say anything.

“As for you,” Leda said, turning to Rylin, “I’ll tell the police what you’ve been doing to Cord. You’ll serve at least ten years for that. Maybe life.”

Rylin blanched. Watt wondered what Leda had on her. Nadia, try to find out, he commanded. Maybe there was some way he could help. If only one of them could get out from under Leda’s thumb.

“I’m not covering for you, Leda, not after—” Avery began, but Leda whirled on her.

“Don’t even think about opening your mouth, Avery. Your dirty little secret is the worst of all.”