Seasons 1-8

Season 1

Dexter Season 1 follows Dexter Morgan, a blood-spatter analyst for the Miami Metro Police Department who leads a secret life as a vigilante serial killer. He follows a strict moral code taught by his adoptive father, Harry, only targeting criminals who have escaped justice.

Throughout the season, Dexter becomes obsessed with the Ice Truck Killer, a mysterious murderer who taunts him with crime scenes designed specifically for him. As the investigation unfolds, Dexter discovers shocking connections between the killer and his own past. Meanwhile, he balances his personal life with his girlfriend Rita, his suspicious sister Debra, and his job at the police department.

The season culminates in the revelation that the Ice Truck Killer is Brian Moser, Dexter's long-lost biological brother. Brian tries to convince Dexter to embrace his true nature by killing Debra, but Dexter ultimately chooses his loyalty to her, leading to Brian's demise. The season ends with Dexter reflecting on his dual nature, now fully aware of his dark past.

Season 2

In Dexter Season 2, Dexter faces his biggest threat yet when his secret life is nearly exposed. The bodies of his past victims are discovered in the ocean, and the FBI launches a massive manhunt for the serial killer dubbed the Bay Harbor Butcher—who is actually Dexter himself.

As the investigation unfolds, Doakes, his suspicious colleague, grows even more convinced that Dexter is hiding something. Meanwhile, Dexter struggles with his urges after temporarily quitting killing, and he begins an intense affair with Lila, a manipulative woman who fuels his dark side.

Doakes eventually discovers Dexter's secret, but before he can expose him, Lila kills Doakes to "protect" Dexter. Realizing how dangerous she is, Dexter ultimately kills Lila. The season ends with the Bay Harbor Butcher case closed—Doakes is blamed for the murders, and Dexter walks free, ready to continue his double life.

Season 3

In Dexter Season 3, Dexter Morgan's life takes an unexpected turn when he accidentally kills Oscar Prado, the younger brother of Assistant District Attorney Miguel Prado. Miguel, initially unaware of Dexter's involvement, becomes close to him, and upon discovering Dexter's secret, they form a twisted friendship, with Miguel encouraging Dexter's vigilantism. However, Miguel begins breaking Dexter's code by killing for personal reasons, leading to a dangerous conflict between them.

Meanwhile, Dexter proposes to Rita, and they prepare for marriage while expecting their first child. The season also introduces the Skinner, a serial killer who abducts and tortures his victims. In the end, Dexter eliminates both Miguel and the Skinner, securing his double life once again. The season concludes with Dexter marrying Rita, seemingly balancing his dark urges with a normal family life—at least for now.

Season 4

In Dexter Season 4, Dexter struggles to balance his life as a husband, father, and serial killer while facing his most dangerous adversary yet: Arthur Mitchell, aka the Trinity Killer. Arthur appears to be a loving family man, but Dexter soon discovers that he is a brutal and methodical serial killer who has been operating undetected for decades.

As Dexter investigates Arthur, he becomes fascinated by his ability to maintain a seemingly normal life. However, Dexter soon realizes that Arthur is far more monstrous than he appears. Meanwhile, Debra uncovers shocking truths about their father and Dexter's past, while Lundy, the retired FBI agent, returns to hunt Trinity—only to be killed by Arthur's daughter's boyfriend.

In the intense finale, Dexter finally kills Arthur but returns home to a devastating sight—Rita has been murdered by Trinity, and their baby, Harrison, is left crying in a pool of blood, mirroring Dexter's own childhood trauma. The season ends with Dexter realizing that his dark life has tragic consequences.

Season 5

In Dexter Season 5, Dexter grapples with guilt and grief after Rita's murder while trying to raise Harrison as a single father. As he struggles with his emotions, he crosses paths with Lumen Pierce, a woman who has been brutally tortured and seeks revenge against her captors.

Dexter helps Lumen track down and kill the men responsible, led by Jordan Chase, a charismatic motivational speaker who orchestrated the abuse. Meanwhile, Debra investigates the case without realizing Dexter's involvement. She ultimately lets Lumen and an unidentified vigilante (Dexter) go, believing they delivered justice.

After avenging her trauma, Lumen decides to leave Dexter, no longer feeling the need to kill. The season ends with Dexter alone again, realizing that despite his efforts, his darkness isolates him from true connection.

Season 6

In Dexter Season 6, Dexter faces a new challenge in the form of the Doomsday Killers, a pair of religiously motivated murderers reenacting apocalyptic prophecies. The duo consists of Professor Gellar and his devoted student, Travis Marshall, though it is later revealed that Gellar has been dead all along and Travis has been acting alone, hallucinating his mentor's presence.

Meanwhile, Dexter explores themes of faith and whether he can pass on a moral code to Harrison. His relationship with his sister, Debra, becomes complicated when she starts therapy and realizes she has romantic feelings for him.

In the season finale, Dexter captures and kills Travis, but just as he finishes the act, Debra walks in and sees him committing murder, setting up a major turning point in the series.

Season 7

In Dexter Season 7, Debra struggles to cope with the shocking truth about Dexter after catching him in the act of killing Travis Marshall. Torn between love for her brother and her duty as a cop, she initially tries to change him but soon becomes entangled in his dark world.

Meanwhile, Isaak Sirko, a ruthless Ukrainian mobster, seeks revenge on Dexter for killing one of his men. Their deadly cat-and-mouse game leads to intense confrontations, but Dexter ultimately eliminates Isaak.

Dexter also becomes romantically involved with Hannah McKay, a mysterious woman with a dark past who understands his need to kill. However, Debra sees Hannah as a threat and works to bring her down.

The season reaches a shocking climax when Debra is forced to kill LaGuerta, who had been investigating Dexter and was close to exposing him. The finale leaves Debra devastated, having crossed a line she never thought she would, while Dexter realizes just how much destruction his life has caused.

Season 8

In Dexter Season 8, Dexter faces his final challenges as he confronts Dr. Evelyn Vogel, a neuropsychiatrist who claims to have helped Harry create Dexter's moral code. She enlists his help in stopping the Brain Surgeon, a serial killer who turns out to be her estranged psychopathic son, Oliver Saxon.

Meanwhile, Debra struggles with guilt over killing LaGuerta, spiraling into self-destruction before slowly finding her way back. Dexter plans to leave his dark life behind and run away with Hannah McKay and his son, Harrison, to Argentina.

However, tragedy strikes when Saxon shoots Debra, leaving her in a coma. Devastated, Dexter makes the heartbreaking decision to end her suffering by unplugging her life support. He then stages his own death in a hurricane, abandoning Hannah and Harrison to keep them safe.

The series ends with Dexter living in isolation as a lumberjack, having exiled himself to protect those he loves from his darkness.