The Matthews' family road trip takes a horrifying turn when they are detoured to a small town from which they cannot leave. When their family RV crashes, Sheriff Boyd Stevens and other residents rush to save them before the sun goes down.
In Sheriff Boyd's absence, Donna and Kenny struggle to manage the chaos as a busload of unwitting newcomers arrives in town; Victor and Tabitha go on a chilling journey through the nightmarish labyrinth of tunnels beneath the town.
A tense night in the diner as the residents and newcomers wait for sunrise; fear permeates the wreckage beneath the Matthews house, as Jim and Tom struggle to keep a panicked bus passenger quiet.
Boyd fears he may have finally run out of answers, as the residents of town prepare for the end; Tabitha clings to the belief that the children could be the key to their salvation.
At Colony House, Tabitha and Julie grapple with their new nightmarish reality. Out in the forest, Jim, Boyd and Kristi struggle to treat Ethan's injuries. Tragedy strikes from an unexpected source as a new threat arises.
In the wake of another death, Boyd questions his decision to leave; Kenny steps up and embraces his new role; Jim rallies the town around his idea to build a radio tower
The Matthews family must choose which of the two settlements they will join. Meanwhile, Jade comes to terms with his situation and Boyd is faced with an impossible decision that strikes at the very heart of life in the town.