Earthweeds

At the end of the world - it's the start of something new, with origins both puzzling and terrifying. A green fog descends over every major city in the world, and the populations disappear one by one. By nightfall, every living soul in every metropolis is gone. Earth grinds to a halt. Only a few stragglers are alive in the rural countryside. When Sam and his brother return from a mountain camping trip, they find only empty city streets. Alone, they look for any survivors to give them answer...