In the heart of the Antarctic Peninsula there's a post office surrounded by jaw-dropping scenery and 3,000 gentoo penguins. Every summer, as staff put stamps on postcards, the penguins return from their fishing grounds to their breeding grounds, trek nearly two miles across sea ice and snow, rush to find a partner, build a nest, lay eggs and protect them from predators, and finally get down to the task of raising their young. We see their four-month drama unfold as cruise ships come and go, bringing tourists to buy postcards and photograph penguins -- the backdrop to the penguins' lives.