Joel Dawson, along with the rest of humanity, has been living underground for seven years following the Monsterpocalypse, ever since enormous beasts gained control of the world. Joel begins to fall for Aimee again after reuniting via radio with his high school girlfriend, who is now 80 miles away in a coastal colony. As Joel realizes there is nothing left underneath for him, he decides against all reasoning to walk out to Aimee, despite the dangers that await him.