Before the pyramids are built, before the Ice Age comes and goes, and before Neanderthals become extinct, the Yam tribe live in peace on Bird Island. But the Crocodile tribe have other ideas …The ferocious Crocodile warriors have already killed Bent Beak’s pa, and now they seem determined to take out his whole tribe. The only way to survive is to flee the island. But where will they go? As the Yam tribe brave the perils of the sea, will they survive the voyage into the unknown, and what awaits them just over the horizon?