A chemical leak from an overturned army truck turns residents of a care home into zombies.

Charlie and Kelly deal with Kelly's nan, as Kelly battles with her conflicting feelings; Steff heads off on a dangerous quest with Finn; Cecily incites the hungry OAP horde, while Frank gets lost, and Jason is attacked.

Kelly's family falls apart; Frank and Cecily seek out new recruits; Finn, with Steff in tow, checks up on Morgan; Charlie, Kelly, Finn and Steff go on a rescue mission.

Relationship problems and exams aren't the only life-or-death situations; a split breaks out among the OAPs as a newcomer turns Frank's head away from Cecily.

Charlie and Steff's friendship is tested; Billy sees an opportunity; Gil starts to realise that her task involves more than meets the eye; residents of Dambury decide that enough is enough.

Billy takes over as heartbreaking revelations threaten the town and her family; residents race against the clock to escape Dambury.