“Cathal,” I said, “it’s a skin. That thing, that blanket the men were using to keep warm, it’s her skin.”

“You mean—” He fell silent.

“Didn’t they say one of the men found it on the shore after Freyja had sailed away? It’s Svala’s—it’s what she wants. I can’t believe it’s taken me so long to work this out. I know dozens of selkie tales. Cathal, we must fetch it here and show him.”

“Him?”

“The creature. I’m sure this is right, Cathal. If I run all the way there and back, maybe we can still get through before the water is too high. This can’t wait for tomorrow.”

Cathal’s eyes passed over the three survivors: Colm now huddled against Gull, sobbing with fear; Donn sheet-white in the gloom; Thorgrim lying limp as if dead on the stretcher, still held above the water by the two stalwart bearers. “You’re saying the rest of us should wait here with that creature breathing in our faces while you run all the way to the cave and back again?”

“That’s what I’m saying.” I had not felt the will of the gods so strongly since the day when I first met Deirdre of the Forest. The runes had not lied. There was a part for me in this mission, and the time for it was now.

“Someone else should go,” Cathal said. “You’ll never carry that thing back on your own. Didn’t you see how big it was?” We stared at each other as the implications of its size sank in.

“I’ll go,” Felix said, moving up beside us. “This is my mission; it is my responsibility. Sibeal and I should go together.”

“No, lad.” Gull spoke, the voice of experience. “If you don’t want to die of an ague on the way home, you’re not going anywhere. Besides, I need you here.” He glanced at the weeping Colm. “Cathal, you go with Sibeal. I’ll keep an eye on things at this end. We’ll lift Thorgrim onto the ledge and cover him up until you get back.” He eyed the creature, which was shifting restlessly, its gaze moving from one man to another as if making a selection. Higher up the tunnel, nearer the cave, I thought the way would be too narrow for the creature to pass. Here, it would be able to move forward and snatch a man in its jaws.

“Sibeal,” Gull said, “if you’ve got some way of talking to our friend here, could you ask it not to eat any of us before you get back? And be quick about it, will you? If anything’s calculated to give me nightmares for the rest of my life, this is surely it.”