The town of Arcadia is in a state of chaos when the return of the deceased reaches a critical mass. Bellamy has no other choice than to ask for outside aid which backfires when Sheriff Fred steps in with his own agenda, triggering a siege on the town that no one saw coming.

With the help of Bellamy and Sheriff Fred, Tom leads the charge in the search for Rachael, but her situation becomes increasingly dire as her captors grow more desperate. Maggie and Dr. Ward continue their medical research on the resurrected subjects and a series of shocking discoveries sets them on the brink of a game changing find, however, their focus shifts when Arcadia is suddenly in the throes of an epidemic.

Maggie turns to a man from her past, Dr. Eric Ward, now working for the NIH, for answers to Arcadia's mystery. She insists Ward is there as a friend, but Bellamy is suspicious of any outsiders. Rachael's secret falls into the wrong hands. In the wake of recent events, Pastor Tom and Bellamy try to reassure Arcadians they have nothing to fear from the returned, but some residents have other ideas.

Bellamy struggles to keep Jacob safe from outside forces. But a tragic incident from his past as a cop continues to haunt him. Elaine is pressured to find out where dad Caleb hid the stolen bank money before the FBI comes to town and learns the truth about Arcadia. Maggie delivers shocking news to Rachael, and Caleb gives Bellamy a chilling warning.

Bellamy and Sheriff Fred form an uneasy partnership to find Caleb, who has gone on the run after Dale's murder. After Jacob suffers a seizure, Maggie gives him a checkup at the clinic and is shocked by what she finds. Pastor Tom adjusts to the unexpected presence of his old love Rachael in Arcadia.

Exhuming Jacob's grave only deepens the mystery of his return. Henry struggles to accept that Jacob is really the son he lost 30 years ago. Bellamy and Maggie search for a connection between Jacob and Caleb's deaths and wonder if the local river may hold a clue. Their digging also unearths Caleb's criminal past - he robbed the bank his daughter Elaine works at just days before his death. Pastor Tom's life is changed forever by a shocking turn of events.

The Langstons, especially Sheriff Fred, are forced to confront secrets from their past they'd rather leave buried when Bellamy pushes to have Jacob's tomb exhumed. Maggie agrees to help Bellamy in his investigation, and Pastor Tom reaches out to Jacob, his childhood friend. The Richards family adjusts to Caleb's return, the second for Arcadia. But unlike Jacob, Caleb claims he has no memory of his death.

The people of Arcadia, Missouri are forever changed when their deceased loved ones suddenly start to reappear.