A group of teens are held up at their small town high school after surviving a chemical plant explosion. What happens to the remaining survivors of their town will shortly invade their space and friends.

After comprehending what has happened to the town, the teenagers start realising what the toxic fumes have done to their friends.

Grover fights to protect Mary. Diesel and Natalie share a secret. Barrett works to contact the outside world.

A new deadly threat turns the survivors against each other. Barrett suggests an unpopular way to gather more information on the freaks.

Lashawn is acting strangely and they think he might be infected, but he is diabetic and he does not have any more insulin. Zoe and Barrett strike an uneasy alliance.

With their water supply cut off, the remaining students come up with a plan to escape. Zoey and Natalie make amends.

The group prepares to take out the freaks in the fallout shelter while unaware that another freak is on the loose. They also discover that Barrett has been lying about the radio.

The students believe they are rescued when someone new arrives at the school. However, he has his own motive for being there and may not offer the help they were expecting.

Diesel gets shot stealing the hazmat suit. Connor breaks free and holds Violet hostage to get it back but the students make sure it's not easy for him to leave. Natalie starts to show the effects of the poison.

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.