A group of tourists is out hiking in the forest when one man slips down a slope and breaks his leg. Jake Langford, a young ranger trainee, is sent in to rescue the hiking party. It is his first rescue. Jake is lowered from a helicopter into the dense forest, and he heads off into the trees looking for the hiking party. Jake soon finds the group and sets about leading them back to the small clearing so the rescue helicopter can extract them. But as they walk away, nobody sees the fallen pair of glasses on the ground, and nobody notices the lens catching the sunlight like a magnifying glass and setting fire to the bone-dry leaves underneath it. Jake leads the party onward, but at the top of a hill they look down and see the fire, already out of control and spreading. It's cutting off their escape route. Jake radios for help, and the smokejumpers soon arrive. But, when they jump out of the plane, they are blown off course, right into the fire. Their parachutes catch fire, and they fall screaming into the inferno. So now, Jake has no choice, with the fire closing in on all sides there is only one possible escape -- an old mine that may let them escape beneath the fire. What Jake doesn't know is that the abandoned mine is unsafe, and worse still, full of pockets of methane, a gas that is not only poisonous but also very, very flammable.