The series premiered on December 13, 2024, on Paramount+. It was initially renewed for a second season in April 2025, but was ultimately canceled in August.
After being shot by Harrison,[a]Dexter Morgan is revived as his life slips away. A young Dexter is interning as a surgeon and is about to graduate. At a fair, Dexter notices a booth featuring Vince Masuka, which piques his interest. Dexter attends a graduation party with his sister Debra. A young man gets Debra drunk and takes her to his room to take advantage of her; Dexter knocks him unconscious, and he and Debra are ejected from the party. Upon their return, their father Harry is awake, worried about them; years ago, Harry lost his son to a careless drowning. While hunting, Dexter tells Harry that killing animals is not enough and what happened at the party, causing him to have a heart attack and being hospitalized. Dexter discovers that the medication the nurse is giving him is killing him; Harry lets Dexter kill her. Dexter kills Mary, the nurse, his first victim; he uses a lake with alligators to make her disappear. Harry recovers and is released from the hospital, and Dexter graduates. Dexter tells Harry that killing Mary felt good, and Harry bursts into tears. Dexter starts working for the Miami Metro Police Department.
In the past, Harry and Bobby Watt are assigned to the Hector Estrada case. They arrested Joe and Laura Moser, who were trafficking cocaine. When Joe refuses, Harry makes Laura his informant for the case. After Harry Jr.'s death, Doris Morgan and Harry try to have another child. In the present, at an unknown location, a boy is kidnapped by a masked man and his finger is severed; the finger is received by Miami Metro. Dexter begins working for Masuka and is dispatched to a crime scene. Dexter tells his colleagues his hypothesis, but they laugh at him in a friendly way. Dexter feels like he has made friends for the first time during a meal. Debra gets angry at Harry for spending too much time with Dexter compared to her. Hoping to make Dexter more normal, Harry asks Angel Batista to take him out at night while Dexter searches the files for free killers so he can kill them. At night, Batista takes Dexter to a club, where he tells him about a loan shark who leaves nothing and kills those he lends. Thus, Dexter gets his next victim thanks to Batista, Tony Ferrer.
Years ago, Harry induces Laura to get closer to Estrada. After the success of the operation, Laura offers Harry sex, but he rejects it. In the present, Captain Aaron Spencer makes the disappearance of Jimmy Powell public, making the case a priority for the police department. María LaGuerta arrives as a newcomer to the homicide department to fill the gaps in the department's solves, much to Spencer's reluctance. Dexter begins to observe Ferrer and gathers evidence to kill him. Dexter, with Masuka's help, obtains a false identity to see Ferrer. Dexter discovers that Sofia Rivera, Debra's friend, has the earrings he kept as trophies. Dexter goes to a jai alai game to see Ferrer; Ferrer gives him a loan. Dexter cooks a cocaine-like recipe for Debra, and she helps him buy some earrings for Sofia and get the other ones back. Ferrer threatens Dexter if he doesn't give him the money within a day, and Dexter gathers evidence to kill him. Harry offers to be present when he does, but Dexter refuses. Dexter incapacitates Ferrer; despite his pleas, Dexter kills Ferrer and disposes of him in the swamp with the alligators.
Years earlier, Harry babysits Laura's sons, Brian Moser and Dexter, to support the Estrada case; Harry begins to grow fond of Dexter. When Laura returns, she and Harry have sex. In the present, Jimmy is found hanging from a bridge, murdered. Dexter becomes anxious upon seeing Jimmy, so Harry sends him to another crime scene; Dexter begins to befriend police officer Clark Sanders. Debra develops a rivalry with a teammate after becoming captain. Dexter finds his new victim, Mad Dog, a mob hitman; Dexter finds potential evidence at Mad Dog's house. Harry and Debra's relationship remains strained. Dexter impresses some teammates after solving a crime, but not LaGuerta. Dexter gathers evidence from Mad Dog and shows it to Harry, and Harry lets him kill him. Debra begins seeing a man named Gio. Dexter goes on a boat trip with Mad Dog. Dexter, at Mad Dog's house, incapacitates him, but he wakes up and runs away; during the chase Mad Dog is hit by a car and dies.
Years earlier, Harry and Laura were still having sex. One day, upon returning home, Doris reveals to Harry that she is pregnant. In the present, following the incident with Mad Dog, Dexter has little time to undo his plan to kill him; the police burst into the house, but cannot find Dexter. Upon returning, Harry berates Dexter for his recklessness with Mad Dog and forbids him from killing or going to work. Debra discovers that Dexter has been eating her marijuana brownies for the team. Debra eats a brownie, they spend the day together, and they reconnect. Dexter, thanks to Tanya, discovers etorphine, a sedative that would allow him to put his victims to sleep for as long as he needs. Harry's job is in danger when he botches a trial, and Levi Reed, a murderer, is released; Spencer retains him but takes him off Jimmy's case. Harry and Dexter leave Debra stranded, and she goes alone to her mother's grave. She spends the day with Gio, and they have sex. Harry attempts to kill Reed, but Dexter sedates him; Dexter uses him as a test for his new method. Dexter wants to kill Reed and suggests it to Harry, to which Harry agrees without hesitation.
Years ago, Laura began to tire of the long time of the case. When Debra was born, Doris told Harry that she knew about his affair and couldn't do it anymore. In the present, Spencer's son, Nicky, is kidnapped by Jimmy's killer. Debra forces Dexter to meet Gio on a double date, accompanied by Sofia. At a crime scene, Dexter theorizes that certain murders are connected, with the killer looking for a method that will satisfy him; LaGuerta rejects the theory. Spencer is informed that his son has been kidnapped; the force worries that Spencer is on the case. Dexter begins to observe Reed. Dexter goes on the double date, demonstrating his social ineptitude; Sofia performs oral sex on Dexter. LaGuerta begins to believe Dexter's theory. Dexter sedates and kills Reed; Dexter becomes a serial killer. With Spencer tense, Harry comforts him. When Dexter goes to get rid of Reed, he encounters the police in the swamp, who have found Ferrer's hand.
Years ago, Harry forces Laura to continue the operation. Laura meets with Estrada and it appears to be a success; Estrada orders that she be kept under surveillance. In the present, Dexter enters the swamp crime scene, where LaGuerta and Masuka are present; Dexter gives Ferrer's hand to an alligator, claiming it attacked him. Dexter disposes of Reed in a dumpster. Sofia leaves Dexter, thinking he is setting her up; Sofia gets angry with Debra when she doesn't support her. LaGuerta tells Spencer about the serial killer theory, and Spencer allows them to investigate. Nicky attacks the captor but misses, and the captor cuts off his finger. Debra punches Tiffany and is kicked off the team; Debra leaves with Gio despite Harry's reluctance. Dexter begins looking for a place to dump his victims. The department receives the finger and confirms it is Nicky's; Dexter discovers possible killer blood. Dexter discovers a wound on Spencer and deduces that he's the killer. Spencer buys cereal, the ones the captor gives to Jimmy and Nicky.
Teleplay by : Mary Leah Sutton Story by : Mary Leah Sutton & Johanna Ramm
January 31, 2025 (2025-01-31)
Years ago, Harry meets Laura publicly, which is witnessed by Jimenez. Later, Laura and her sons are kidnapped and taken to a shipping container with other captives, where Estrada and his men reveal they know she is a snitch and kill another captive in front of them. In the present, Dexter tells Harry his theory about Spencer, but Harry refuses to believe it and orders him to find Debra, who is missing. Dexter notices Spencer give a bag to a man who goes to a cartel house, and eventually discovers Gio has a fiance and has taken Debra to Bimini, where he picks her up after Gio abandons her. Taking her home, he realizes he can use the ocean to dispose of his victims. Harry and LaGuerta follow a lead to Tampa, where they find another victim, Dr. Petrie, a therapist. Harry finds one of his patients was Brian Moser, and hides this from LaGuerta. Spencer sets up a raid on the cartel house, and after finding Nicky's shirt, stages a breakdown and initiates a shootout with the cartel members, in which Bobby is critically shot. Realizing Spencer is the killer and orchestrated the events, Dexter decides to stop him.
Teleplay by : Scott Reynolds Story by : Scott Reynolds & Alex Kellerman
February 7, 2025 (2025-02-07)
Years ago, following the massacre, Harry finds Dexter and Brian in the shipping container. Due to their mother's death, he and Doris attempt to adopt them, but return Brian to social services after he nearly asphyxiates Debra. In the present, Brian kidnaps and kills his former social worker Barb. When confronted, Harry admits his connection to Brian to LaGuerta but conceals the fact that Dexter is also connected. Following the shootout, the police organize a blood drive for Bobby, which Debra and Dexter participate in, and Debra finds she is still considered for a volleyball scholarship. Harry discovers Brian was present at all the crime scenes, realizing he killed the victims to observe Dexter investigating. Dexter lures Spencer into a trap and captures him. Spencer admits he used Nicky to get back at his ex-wife for cheating on him and turning the boy against him. Dexter severs Spencer's finger and slightly loosens his restraints, allowing him to escape, and discreetly follows him to Nicky's location.
Teleplay by : Clyde Phillips Story by : Clyde Phillips & Alexandra Franklin & Marc Muszynski
February 14, 2025 (2025-02-14)
For years, Brian went through several foster homes, each with problems, until he was finally admitted to a mental institution. During a therapy session, Dr. Petrie forbids him from seeing Dexter, so Brian kills him and leaves. Dexter follows Spencer to a ship where Nicky is being held. Dexter catches his attention, and Spencer tries to kill him, but fails. Spencer begins flooding Nicky's cell and gives Dexter the choice of saving Nicky or chasing him; Dexter saves Nicky, and Spencer flees. Harry goes with LaGuerta to the crime scene of Barb and spots Brian in the distance. Harry confronts Brian about the murders and his desire to be with Dexter and tries to stop him, but Brian claims he can only kill him; Harry can't, and Brian knocks him out. Spencer goes to Becca's house to kill her, knowing that Nicky is not his son, but Dexter knocks him out. On a boat, Dexter kills Spencer and throws him into the sea. Harry complains about being blinded by Spencer, but Dexter comforts him. Bobby leaves the hospital. At a dinner, Debra announces she wants to join the police, and the family celebrates together, with Brian looking on in the distance.
Production
Development
On February 6, 2023, Showtime gave production a series order for an origin-story prequel for Dexter, titled as Dexter: Origins created by Clyde Phillips.[2] It was later retitled as Dexter: Original Sin and will consist of 10 episodes. Phillips, who serves as the showrunner, is also expected to executive produce alongside Scott Reynolds, Michael C. Hall, Mary Leah Sutton, Tony Hernandez, and Lilly Burns, with Robert Lloyd Lewis serving as a producer. Production companies involved with the series are Showtime Studios and Counterpart Studios.[3]
In March 2025, showrunner Clyde Phillips said of a second season "I honestly don't know. I'm busy shooting Resurrection now and haven't been thinking about the next season of Original Sin. We'll see." Cast members have said that they would be open to return for another season. "I had such a great time doing this and everybody involved is so incredible. To have Clyde [Phillips], the original showrunner, involved and still doing it, and the cast was also great that I would feel so, so lucky to come back again" Patrick Gibson said.[4] On April 1, 2025, the series was renewed for a second season at Paramount+ and Showtime.[5] On August 22, 2025, Dexter: Original Sin was canceled, reversing the renewal.[6]
Upon its release Dexter: Original Sin became Showtime's most streamed premiere with over 2.1 million global cross-platform viewers.[16]
Review aggregator website Rotten Tomatoes reported a 70% approval rating with an average rating of 6.6/10, based on 20 critic reviews. The website's critics consensus reads, "Original Sin cares less about injecting fresh blood than reviving a tried-and-true formula, making for a prequel that's just solid enough to scratch the Dexter itch with a scalpel."[17] According to Metacritic, which calculated a weighted average of 50 out of 100 based on six critic reviews, the series premiere received a "mixed or average" response.[18]