Earth, 2099. Global warming is devastating the climate. The polar ice caps are melting. In a desperate attempt at preservation, the governments of the world have removed vast sections of the Arctic and Antarctic and set them inside huge domes across the world. The Doctor and Martha arrive in Snowglobe 7 in the Middle East, hoping for peace and relaxation. But they soon discover that it's not only ice and snow that has been preserved beneath the Dome.