By 1896 conservationist Richard Henry was so alarmed at how introduced pests had decimated the kākāpō, New Zealand's largest parrot, that he spent four years relocating 400 birds to Resolution Island. Then he discovered ferrets had beaten him, and his efforts were in vain. By the mid 1970s the kākāpō population numbered just 12 birds. This documentary follows NZ Wildlife Service leader Don Merton's rescue team, who after two years scouring Milford Valley locate two male birds and transport them to pest-free Maud Island in the Marlborough Sounds. But there's a problem — only one female remains.