Usually our fears are nothing more than a figment of our imagination, but for the family members of deceased cancer patients at Hessberg Medical Center, fears have become a reality.
Audrey and Nathan are called to the murder scene of Bill Rand, a well-known nurse at Hessburg Medical Center. Apparently, someone wielding a large sword-like object attacked him as he staggered home in a drunken stupor.
After interviewing Mrs. Wilson, the director of the hospital, and several family members of the deceased, Audrey and Nathan are introduced to the idea of "The Dark Man". Everyone believes that the "The Dark Man" killed their loved ones who, even though they were diagnosed with terminal cancer, died way before their time. They all realize that their claims seem far-fetched but they're determined to share stories about their personal encounters with "The Dark Man".
Later on while sitting on her couch, Mrs. Wilson is killed in a similar manner as Bill. Audrey decides to exhume the bodies of the cancer patients to determine any similarities between the deaths. The bereaved family members, especially Thorton whose wife Sarah-Beth died of cancer, do not approve but Audrey continues with her plan.
Meddling in the matter summons The Dark Man, who pays Audrey a visit that night at the precinct. Perhaps he wanted to show her that there were consequences for disturbing the dead? In a state of panic, Audrey realizes that the The Dark Man (which in essence is a shadow folks) cannot function in total darkness. So, she lunges for the surrounding light switches and waits for Nathan —who was in the middle of er… "hanging out" with Jess —to help her.
Shortly after, the autopsy reports of the exhumed bodies return and show that none of the patients were treated for chemotherapy. It turns out that Bill and Mrs. Wilson were pocketing money by not distributing the medicines.
In a twisted turn of events, The Dark Man attacks Jess (but doesn't kill her) after she visits Thorton and discovers that Sarah-Beth never took her medication. Nathan and Audrey's "ah ha" moment comes when they realize that Thorton's shadow is missing. This assures them that he is The Dark Man — something he was completely unaware of. Apparently, when his wife died his shadow left him and took on any pain or anger he was feeling, so that he wouldn't have to deal with it himself. It turns out that: (1) whoever Thorton is upset with, his shadow goes after them and (2) the patients actually died because they weren't given the proper medication.
In the end, "The Dark Man" returns to Thorton but what lies ahead for the two of them remains a mystery for now. Unfortunately, Haven was too much for Jess to handle so she decides to move to Montreal, leaving Nathan heartbroken but able to now feel human contact. Go figure.
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.