View the return of wildlife to Mount St. Helens — and the threat of another eruption.

When Mount St. Helens erupted in 1980, every living thing in the blast zone was buried beneath 300 feet of avalanche debris, covered with steaming mud and, finally, topped with a superheated layer of frothy rock from deep within the earth. Over the course of 30 years, biologist Charlie Crisafulli documented the dramatic return of plant and animal life to the barren landscape. But he also tracked a new threat: The mountain, like the wildlife, is coming back to life. Soon after the 1980 eruption, new lava was bubbling up to the surface, and in 2004, a flurry of explosions blasted steam and ash thousands of feet into the air. What force is driving this baffling pattern? Using GPS, magnetic mapping and more, geologists track the movement of magma deep within the volcano and reveal a hidden lattice of faults that lies beneath the volatile landscape. NOVA presents a pioneering look at the interplay between biology and geology that may help scientists predict future volcanic eruptions.