Hajime Arakawa, a high school student worried about his future, runs away from home after arguing with his mother. Suddenly, a terrible earthquake occurs, followed by the mysterious appearance of numbers in the sky. Hajime runs home in search of his mother, but finds to his horror that she is no longer the same...
In a world where all the adults have turned into monsters, how will the children survive?

Hajime Arakawa, un estudiante de secundaria preocupado por su futuro, huye de casa tras discutir con su madre. De repente, se produce un terrible terremoto, seguido de la misteriosa aparición de números en el cielo. Hajime corre a casa en busca de su madre, pero descubre horrorizado que ya no es la misma...
En un mundo en el que todos los adultos se han convertido en monstruos, ¿cómo sobrevivirán los niños?