Because of family reasons, high school girl Emma (Sofia Black-D'Elia) moved to Shadow Canyon, California with her father (Michael Kelly), who teaches biology. During this period, a terrible worm spread throughout the world, many countries were devastated, and crises in various states of the United States also emerged one after another. One day in class, Emma's good friend suddenly fell ill and ran away, and the school was forced to close. After that, the epidemic spread rapidly. The father went to the airport to greet the trapped mother, while Emma and her sister Stacey (Analeigh Tipton) stayed at home. Not long after, the US President announced martial law in California. People living in the epidemic area were not allowed to enter and exit at will, and those who were infected were always threatening the lives of the survivors. During this period, Evan, the boy Emma liked, also ran to her home for refuge. And Stacey was infected at a previous party...