This latest thriller takes the Landons to Alaska, where wildlife biologist Olivia and her photographer husband, Steven, have been asked to study the impact of snowmobiles on the wolverine population of Denali National Park. With the family is 13-year-old Nicky Milano. When a man in a Park Service uniform offers to take Jack, Ashley, and Nicky on a dogsled ride, the kids eagerly accept. They mush off across the snow, riding deeper and deeper into the frozen wilderness. But during a rest stop, the man suddenly rushes off, leaving the young people stranded. As they huddle to keep warm and try to figure out what to do, they hear a deafening roar. Avalanche! Now the kids must fight for their lives. Can they somehow escape the thundering mass of snow? Or will they be buried alive?