Yosemite Valley is a land forged in wildfire and sculpted by water, the delicate balance of these two elements are essential to the creatures and trees that call this land their home. But with climates changing and temperatures rising, the Sierras are under siege. Water is scarcer and the threat of fire is more common. Join scientists, experts, and adventurers as they trudge through mountains of snow, climb trees as tall as buildings, and soar high in the air to spy just how these global changes are affecting one of America's greatest wildernesses.