“So, what the hell happened last night?” Alex asked her directly.

“I have no idea.” Harper shook her head and sat down in the chair in front of her desk. “I don’t even know what those … those things were.”

“I can barely even remember what they look like anymore.” His brow furrowed as he tried to think. “Last night’s a weird blur of images that don’t even make sense.”

“That’s probably because you hit your head,” Harper said.

Alex seemed to think about it for a minute, then said, “No. I don’t think so. I remember everything really clearly until we were in the cove and that song started.”

Harper had actually forgotten about the song until Alex mentioned it. She couldn’t remember the words, but the melody surfaced, like a half-forgotten dream.

There were a few minutes in the cove that Harper couldn’t really remember, either. The events were a haze of confusion, though she recalled a longing and a pull toward the phantom song. Daniel had helped keep her from diving into the ocean the way Alex had, but that was about all she could remember until they were on the boat again.

“Did you swim to the island?” Harper asked, realizing that he must have.

“I think so.” He shook his head again. “I can’t really remember much. There was the song, then I was swimming, and then I was on the island. Those pretty girls were there, and … and Gemma. She kissed me…” He swallowed hard.

“Do you remember the creature?” Harper asked.

“The bird?” Alex asked, and she nodded. “Is that what it was? A really big bird?”

“It was more like a bird-monster,” Harper tried to explain. “But then it changed and turned into Penn.”

“So those pretty girls are some kind of shape-shifters?” Alex asked. “Because they turned into fish, right? Gemma and the girls turned into fish, then swam off?”

“Mermaids, I think,” Harper corrected him.

“This is so insane,” Alex said quietly, almost to himself, then he looked up at Harper, his dark brown eyes locking seriously on hers. “Stupid question time, but I have to ask. Gemma hasn’t, like … always been a mermaid, has she? This isn’t some family curse thing like on Teen Wolf?”

“No.” Harper smiled despite herself and shook her head. “No. There’s no history of mermaids or any other mythological beings in our family.”

“Okay. Good,” Alex said, then changed his mind and wagged his head back and forth. “Well, not really. If you knew what this was, it would be easier to deal with.”

“It certainly would,” she agreed.

“So you don’t have any idea what Gemma or Penn or the girls might be?” Alex asked.

“No,” Harper admitted regretfully.

“And you don’t know where they went?”

“Nope.”

“So. How are we gonna get her back?” Alex asked.

“Well…” Harper took a deep breath. “We figure out what they are and how to stop them, then we find them and we take Gemma back.”

TWO

Metamorphoses

Marcy had been talking for a while, but Harper hadn’t been listening. She sat at the desk, staring into space and trying to figure out what to do.

When Alex left the night before, they’d both agreed that they had to continue on with life like normal until they found Gemma. That meant going to work, even when Harper would rather be at home scouring the Internet for clues about what Gemma might have become.

She’d spent a lot of time on sites that claimed to be experts on Bigfoot and el chupacabra, but nobody had heard of a bizarre bird-monster that also turned into a fish-human hybrid and a beautiful teenage girl.

By the time she fell asleep very late last night, Harper had begun to believe that she’d made up the whole thing. It was some weird stress-induced hallucination. That was the only logical explanation for what she’d seen.

“But I was like, you can’t make a fur coat out of basset hounds,” Marcy was saying when Harper started tuning back in. “It’s not like I’m Cruella De Vil, you know?”

“No, it’s not,” Harper replied absently.

Marcy scoffed and stared at her above her dark-framed glasses. “You haven’t listened to a word I’ve said, have you, Harper?”

“You’re not Cruella De Vil.” Harper forced a thin smile at her.

Marcy rolled her eyes. “Lucky guess.”

“How is that lucky?” Harper asked.

The bell of the library’s front door rang as it swung open, and Harper pulled her eyes away from Marcy’s annoyed gaze to see Alex come striding over to the desk. He grinned broadly, which was a massive change from the grim expression he’d worn last night.

“You heard from her?” Harper blurted out, interrupting Marcy midsentence after she’d begun talking about basset hounds again.

“No.” Alex’s smile faltered for a moment as he rested his arms on the desk in front of her. “But I do have good news.”

“Yeah?” Harper leaned forward.

“I figured it out.” His smile returned as brightly as before. “Sirens.”

“Sirens?” Harper frowned in confusion. “Like police sirens?”

“Is this about Gemma?” Marcy asked, managing to sound concerned for once. “Did the police find her?”