Seven years ago, humanity blew up an asteroid that was approaching Earth, but afterward faced the consequences — some of Earth's inhabitants mutated into giant monsters. Within a year, Earth's population had fallen by 95%. Joel's parents died, and since then he lives in an underground bunker among other survivors. Recently he picked up a radio signal from another colony, where his teenage love Amy lives, and now he's decided to reach her. And this will not be easy, for Joel has no survival skills, and more importantly — at the sight of monsters he freezes up.