After burying his father with Duke's help, Nathan is having a memorial service for the Chief at The Grey Gull and all of Haven has shown up to support him except, oddly enough, Duke. Turns out Duke is being stalked by a masked man during his regular beer run. In fact, all of the people in the grocery store with Duke are experiencing their worst nightmare.
Back at the memorial, the two Audreys are still getting to know each other but Audrey #2 has set her sights on talking "the real" Audrey's boss, Agent Howard, to sort things out. Meanwhile, Nathan discovers he can feel pain—quite a boon for him.
When word of Duke's encounter gets back to Audrey, she goes to investigate with Nathan and Audrey #2 in tow. It soon becomes clear that the people in the store were hallucinating, but who caused it? Thankfully, a new riot at the bus depot provides another location to investigate. This time, even Audrey #2 is affected and she almost shoots an imaginary clown that both Audreys remember from childhood.
After the search leads them to a young lady named Jackie Clark, who might be causing these visions, the team tries to find her while Duke is coerced into taking his old "friend" Ian north to Canada for reasons unknown. Ian leaves just as Audrey #2 arrives looking for Agent Hudson. Duke points her in the right direction and, eventually, the two Audreys find that Howard left them a clue in the form of a familiar book.
At Jackie's house, Audrey and Nathan find Jackie's boyfriend, Brian, who unwittingly slashed Jackie when he thought he was seeing a burglar. Luckily, she didn't get far. They find Jackie across the street getting bandages. Since Audrey is immune to Jackie's power, she's able to bring her in. Nathan, however, isn't so lucky.
After interviewing Jackie, Audrey thinks that maybe someone else in Haven is able to take "afflictions" by cutting the afflicted person. That same person must have taken Nathan's ability to not feel pain. The culprit appears to be Ian, who climbed down a narrow chimney to steal an ancient puzzle board from a local museum: a puzzle that has the power to destroy whole buildings— and even the town itself.
Once Audrey and Nathan figure it all out, they deduce that Ian stole Jackie's power in order to collect the pieces of the puzzle board and then stole Nathan's power to acquire the board itself. They rush to Duke's boat where a standoff ensues. When the smoke clears, Ian is dying but Nathan makes sure that he dies with Jackie's affliction, which sadly leaves Nathan to cope with his inability to feel again.
Colin Ferguson gives his final thoughts on the season finale of Haven.
In Haven's fourth season finale, William's plan to turn Audrey back into her original self, collides with Audrey, Duke and Nathan's plan to trap William back in the dark place he came from.
Get a look at the references to Stephen King's works from the season 4 finale.