A couple and their friends find themselves frightened when they discover the Mysterious Woman Killer is on the verge of hunting women.
- Jorge Hollister (Ryan Kelley) - the film's main protagonist, who discovers from his mother that his father was killed by the Woman Killer when he was a baby, in the end, He ends ups stranded on the island with Gertrude.
- Gertrude Potter (Melissa Benoist) - the film's deuteragonist, Jorge's love interest, who he helps with the Woman Killer, as she and Harrison's best friend, she intends to find out that the Woman Killer suffers from rejection, in the end, She is stranded with Jorge and tells him that the murders are over.
- Harrison Morrison (Corey Hawkins) - the film's tritagonist, Gertrude's best friend, he and Gertrude found a clue that the Woman Killer suffers from rejection, in the end, He was seen with Aaron and is searching for Jorge and Gertrude.
- Aaron Trask (Idris Elba) - a convict who was imprisoned because he was framed by the Woman Killer into thinking he killed his wife, near the end, he teams up with Gina (who was framed by his jealous friend) escape so they could stop the Woman Killer, while Harrison lets him avenge his wife, in the end, is seen helping Harrison search for Jorge and Gertrude.
- Horace Proctor (Iain de Caestecker) - Aaron's jealous friend and rival when Gina loves Aaron for himself, unaware he is cheating his girlfriend, He finds a clue about the Woman Killer, in the end, was killed by the Woman Killer after framing Gina.
- Gina Stagg (Katie Stewart) - Horace's girlfriend, near the end, when he discovers she was cheating on him, she was framed when she discovers him dead, and was killed saving Aaron.
- Ingrid Hollister (Morena Baccarin) - Jorge's mother and a widower, who lost her husband to the Woman Killer when he was a baby, she was killed by the Woman Killer when she spoke, "I know who you are, you took my husband, widowed me, broke me, when my son finds out who you are, you'll be sorry you ever messed with him", before getting stabbed..
- Commissioner Mathias McCloud (Adrian Pasdar) - the Police Commissioner, who is a good man wanting to clean corruption out of the city of Orion, running for Attorney General, in the end, he wins the election and drops charges on Aaron and proves his and Gina's innocence.
- Eva McCloud (Kim Raver) - Mathias's wife, who believes him to be a good man, cleaning the corrupt from the city of Orion, in the end, she is pregnant with child.
- Chief Eustace Grady (Vincent D'Onofrio) - the Police Chief, who is hunting down the Woman Killer, and is very loyal to Commissioner McCloud, near the end, he decides to help Aaron under the condition that he cooperates with him, in the end, he was killed by the Woman Killer.
- Marcie Desmond (Gina Torres) - the Police Lieutenant who aids Chief Grady, in the end, becomes Grady's successor.
- Neil Hollister (Jason O'Mara) - Jorge's father who was killed in the flashbacks by the Woman Killer
- Dr. Leonidas Fisher /Woman Killer (Zeljko Ivanek) - the film's main antagonist, who is hunting down women and killing them, in the same vein as Jack the Ripper, near the end, we discover he had suffered rejection a long time ago before Jorge was born, he used to love his mother, but she left him for Neil (which was the reason why he killed her), and ends up marrying Neil, who he forces to cooperate with his plan of covering his activities. He was in the end killed by his own blade within his boat and was eaten by sharks.