“If Eriana is part of the serpent,” said Nilus, “can I ask why you want to destroy her?”
“Destroying the serpent means freeing Eriana’s soul from its host. The legend is complicated. But—” I glanced around and lowered my voice again. “Nilus, I might not even have to.”
He looked at me sharply. I pressed on.
“If I can keep her under my control, I can use her to make sure nothing like this happens to our people ever again. This is what Eriana used the serpent for in the first place. I’d be continuing her legacy.”
Something worked behind Nilus’ expression. I couldn’t tell what it was. Did he agree, or did he think I was crazy? A long-forgotten desire for my big brother’s approval bubbled up inside me.
I was beginning to wish I hadn’t said anything when Nilus looked at something over my shoulder, and I turned to see Lysi and Ephyra in the doorway.
“Sorry to disturb you,” said Ephyra, “but the sun is setting, and these girls don’t have a place to sleep.”
Nilus threw an arm across my shoulders. “Priorities! Let’s get you settled.”
The four of us swam a short ways to an empty grotto. We covered the entrance with kelp weeds and used a rawhide bag to pull down a fresh pocket of air for the ceiling.
After saying goodnight to the others, Lysi and I stayed awake. Though we were far enough north that night would not fall at this time of year, the curtain of seaweed and depth plunged us into blackness.
“I found out something from Ephyra,” whispered Lysi. “Up here.”
We surfaced inside the air pocket to stop our conversation from carrying outside the grotto. There, Lysi relayed in a whisper what Ephyra had told her about Adaro disappearing during king tides, and that the Reinas were planning the attack around that time.
“Wait, I don’t get the pattern,” I said. “I thought tides cycled every twenty-eight days with the moon.”
“They do.”
Lysi raised a hand above the surface. Water trickled from her fingers. I felt through the darkness and placed my palm against hers.
“So what’s a king tide? Why is it only a couple of times a year?”
“It’s about the moon’s orbit and phases. Tides happen because the moon and the earth are attracted to each other. The moon tries to pull the earth towards it.” She closed her hand over mine and pulled me in so our noses touched. “But the only part of the earth that obeys is water.”
Slowly, she pushed me away, and then pulled me in again. Water sloshed against us and the rock walls.
“The strongest pull marks a new tidecycle. But the moon’s phase also has an effect. When the moon is full or dark, it has a stronger pull than usual. High tides get higher; low tides get lower. When a new tidecycle coincides with a full or dark moon, the tides are extra strong. This is a king tide.”
I stopped her pulling me in again. “And Adaro disappears for a day every time this happens.”
Lysi dropped my hand. “Yes.”
I stared into the blackness. What were we missing? What did the combined pull of a new tidecycle plus the moon’s phase mean? I’d never properly learned about tides, except for the tracking I’d done as a kid so I could meet Lysi at low tide.
I grabbed her hand again, sorry her explanation was over. I pulled her close so I could feel her breath on my face.
“How long until the next one?”
“It’s going to happen next tidecycle—and after that, not again until winter.”
I chewed my lip. That meant we had a month until the Reinas would storm Utopia. It wasn’t soon enough. Adaro could destroy the entire coast by then. We needed to act now.
“They’re using us,” said Lysi in barely a whisper. “The serpent is the only reason Dione wanted me here.”
“I know.”
“She wants to talk to us again. What do we tell her?”
“Nothing. Not without the promise that they’ll help us get to Adaro.”
