Beneath the tranquil rivers and majestic hills of Yellowstone National Park lies a giant hotspot of volcanic activity. Now, after lying dormant for thousands of years, this "super volcano" is threatening to erupt and wipe out much of North America. As lava races through the park and tourists run for their lives, it's up to Yellowstone's top scientist and a fearless park ranger to put aside their differences and come up with a plan in time to save the world.