That night they walked hand in hand beneath the great equatorial moon, beside the Restless Sea.
"Soon," said Nu, "Nat-ul shall become the mate of Nu, the son of Nu. Nu, my father, hath said it, and so, too, has spoken Tha, the father of Nat-ul. At the birth of the next moon we are to mate."
Nat-ul nestled closer to him.
"My Nu is a great warrior," she said, "and a great hunter, but he has not brought back the head of Oo, the killer of men and mammoths, that he promised to lay before the cave of Tha, my father."
"Nu sets out at the breaking of the next light to hunt Oo," he answered quietly, "nor will he return to claim his mate until he has taken the head of the killer of men and mammoths."
Nat-ul laughed up into Nu's face.
"Nat-ul but joked," she said. "My man has proved himself greater than a hunter of Oo. I do not want the great toothed head, Nu. I only want you. You must not go forth to hunt the beast—it is enough that you could slay him were he to attack us, and none there is who dares say it be beyond you."
"Nevertheless I hunt Oo on the morrow," insisted Nu. "I have never forgotten my promise."
Nat-ul tried to dissuade him, but he was obdurate, and the next morning Nu, the son of Nu, set forth from the cliffs beside the Restless Sea to hunt the lair of Oo.
All day Nat-ul sat waiting his return though she knew that it might be days before he came back, or that he might not come at all. Grave premonitions of impending danger haunted her. She wandered in and out of her cave, looking for the thousandth time along the way that Nu might come.