Dwight struggles to maintain order when Duke's trouble wreaks havoc around town; at the same time, Audrey and Charlotte work together to drive away a mysterious fog that has everyone trapped in Haven.

Desperate conditions in Haven lead to a terrified population that's difficult for Dwight to maintain control over; at the same time, Nathan assembles a task force to restore power to the town; and Audrey tries to put an end to the trouble once and for all.

Dwight and Charlotte work to clear Nathan's name when the citizens of Haven put the lawman on trial. Hoping to buy them time, the brothers Teagues moderate the courtroom proceedings, while Audrey continues her quest to solve the darkness troubles.

Nathan and Dwight race to rescue Audrey from Croatoan, but the consequences of Duke's dark destiny wreak havoc on their plans. Meanwhile, Vince contemplates an unusual sacrifice.

Nathan struggles to return to Haven as Dwight reconsiders his future in the series finale, which also finds Audrey coming to a terrifying decision about how she might finally save the town from Croatoan.