Emma and her sister Stacey are normal teenagers in a small town, when a mysterious infection begins to spread. With the town quarantined, and their parents stuck on the other side of the barrier, the girls have a blast eating junk food and sneaking out to go to parties. But when the disease starts to infect people they know, the girls, together with their neighbor Evan (Emma's secret crush), barricade themselves into their home. But it may already be too late, as the infection is already in their midst, and Emma will be faced with a choice: protect her sister or survive the virus.