Things come to a head when a traitor is revealed. One of the group makes a sacrifice as more secrets about the explosion are brought to light.
As suspicions amongst the survivors grow, one member of the group goes rogue. Grover unintentionally reveals a secret and Violet feels betrayed.
One of the group must venture outside to look for help. Diesel reassesses his relationship with Natalie.
The situation with the intruders reaches a boiling point. Violet puts herself in a dangerous position to save the others.
Running low on resources, Violet and Zoe take on a dangerous mission. Zoe and Natalie address their past.
LaShawn returns to the high school, followed by a group of people, who present a grave threat to the kids at the school.
Grover fights to protect Mary. Diesel and Natalie share a secret. Barrett works to contact the outside world.
Lashawn is acting strangely, and the kids begin to suspect he might be infected. Zoe and Barrett strike an uneasy alliance.
The group tends to their sick classmates, but they soon discover that the peculiar illness is more than meets the eye.
A group of teenagers gather at their high school for Saturday detention, only to be trapped inside when the chemical plant in their small town explodes.
