Between is the story of a town under siege from a mysterious disease that has wiped out everybody aged 22 and older. The series also explores the power vacuum that results when the government quarantines the town within a 10 square mile diameter and leaves the inhabitants to fend for themselves.
A mysterious virus begins to kill off adults in the small town of Pretty Lake, and those left alive scramble to survive. Wiley Day is pregnant but she has a plan to give up the baby and leave Pretty Lake behind forever until the government implements a quarantine of a 10-mile radius around the town. Trapped inside, Wiley's best friend Adam, whose plans to attend MIT are dashed, knows their only hope of escape is to find the cause of the virus.
The survivors in Pretty Lake collect the dead and hope to have the quarantine lifted. Adam meets a man with a mysterious past. Wiley seeks hush money.
Tensions escalate as a power outage cuts off communication with the outside world. A text suggests Ronnie is involved in something sinister.
Chuck continues enforcing his brand of "justice" in Pretty Lake. Meanwhile, Ronnie and Wiley draw closer, and Adam helps Ms. Symonds celebrate her 22nd birthday.
The residents of Pretty Lake remain cut off from the outside world but, on the bright side, their power has been restored.