Halfway between New Zealand and Antarctica the rugged Auckland Islands, formed from the crumbling remains of two 12 million year old volcanoes are a beacon of life in the bleak southern ocean. Every summer the island's population explodes as regular visitors arrive - some to mate and produce their offspring, while others are there to prey on the newborns. A massive congregation of New Zealand sea lions forms on the sandy beach, and brawling males battle for mating rights, while females give birth. Beneath the waves, male giant spider crabs migrate from the depths to the islands coast to seek females and perform their bizarre breeding ritual. Yellow-eyed penguins, and other year round residents, must adapt to the new arrivals if they are to survive.