It's 2048, and the world has been ravaged by a lethal virus. Will Collins, the last surviving resident of a Buddhist retreat center in Colorado, receives an urgent and mysterious request: to deliver a potential cure to a scientist on the West Coast. So Will sets out into an unknown and perilous world, haunted by dreams of the woman he once loved, in a rusted-out pickup pulled by two mules. He doesn't have much time--temperatures are rising to lethal heights, a hit man is on his tail, and armed militias patrol the roads. The only way he'll make it is with the help of a clever raven, an opinionated cat, and a tough teenage girl who has learned to survive on her own.