A group of gray wolves silently stalks prey. Once the pack picks one of the older animals in a herd, the apex predators take it down with the speed and strength that no single animal would have been able to manage. All around them, plant life grows lush, healthy bison roam the land, and an eagle picks apart leftovers from the pack's last kill. Wolves are vital to their ecosystems, controlling the size of prey populations so all life can flourish. Uncover the truth about this important keystone species, explore how wolves shape entire ecosystems, and learn what's at risk if these powerful predators disappear.