On her way home that evening Luce noticed a series of dots in the water ahead of her. They appeared to be moving south, and her heart skipped hopefully. As quickly and quietly as she could Luce sped along below the surface, passing her own cave, until she was just close enough to confirm that what she’d hoped was true. Through the dim green water she could see the rapid, graceful flash of mermaid tails all swimming away together. Rachel had done her job well, Luce thought. The tribe was as safe as it could be now. If the humans found their old cave it would be nothing more than a vacant, garbage-strewn hole.

She stopped to gather a supply of oysters, then turned to go home. Once she was back in her own cave Luce realized that she was now truly the only mermaid living on this stretch of the Alaskan coast. She felt more alone than she ever had before, but she told herself it didn’t make sense to feel that way. Not when she had Dorian.

∗ ∗ ∗

A few days later Luce woke to find a fresh skin of ice covering the water of her cave. It was thicker than the time before, stretchy and as dark as the water below it. She tore through it easily enough, but she couldn’t help imagining that soon it might be harder to break free. When she went to meet Dorian later that day she found that the water near the shore was covered by an elastic veil of nilas some three inches thick. It bellied and fell with the waves, tearing in places, so that sheets of soft ice overlapped one another in ridges. Luce rounded the boulder that sheltered their meetings from view and looked at Dorian standing on the far side of the bending ice. He was about twenty feet away from her.

“I could try to walk out on it,” Dorian called doubtfully.

Luce felt sure it wouldn’t support his weight. “Stay there, okay? I’ll break through from the bottom.” Luce swam along the seafloor until the ice ceiling pressed claustrophobically against her head, then drove herself upward. The ice sheet swelled above her while she drove up with her fists, finally bursting through at Dorian’s feet. He knelt down, and his hands slid tenderly around her shoulders.

“Luce,” Dorian said immediately, “I’m really getting worried.” He was gazing out anxiously at the shuffling white blots of pack ice on the distant waves. “What if you got trapped under the ice somewhere and it was too thick for you to break and you couldn’t breathe in time—”

“It wasn’t like this last winter,” Luce told him, as if that could change anything. “The tribe stayed here, and they said the ice wasn’t bad at all . . .”