Riley and her family fly north to Churchill, Canada, to watch polar bears hunt seals from the ice of the Hudson Bay. There's just one problem: no ice! For polar bears, no ice means no seals, and without food, the bears can quickly become hungry, weak, and dangerous! It's a race against time as everyone searches for clues to this puzzling climate mystery. Will the ice freeze in time, or even at all? And will the polar bears finally eat again?