An otherworldly force opens a gate in a remote mountain range in Colorado and unleashes an alien organism into the forest. Once the gate opens, a shield is placed over the entire area blocking all communications in or out of the zone. It then releases a time pulse every 30 minutes locking everything inside the shield into a checkpoint. If anything destroys the gate, everything within the shield is reset back to the previous checkpoint before the gate was destroyed. The organism is highly infectious and anything it touches mutates and joins the invading force. They become soldiers with a darker will and help spread the infection even further. Survivors caught within the shield try to escape and stop the organism from leaving, but something keeps destroying the gate, resetting time, and changing their fates.