The season opens with Dexter Morgan grappling with the aftermath of the previous season's events, particularly the death of his sister, Debra Morgan. He is haunted by her shooting and struggles with his emotions, feeling a deep sense of loss and guilt. Dexter is also trying to maintain a semblance of normalcy in his life, continuing his work as a blood spatter analyst for Miami Metro Police Department while secretly pursuing his dark urges.

Dexter's relationship with Hannah McKay, a former assassin, becomes a focal point. He is drawn to her, and they begin a romantic relationship. However, Dexter is conflicted about his feelings for her, especially as he contemplates the implications of being with someone who has a violent past. Meanwhile, Debra is recovering from her injuries but is deeply affected by her experiences, leading her to question her own morality and the choices she has made in her life.

As the season progresses, Dexter learns that a new serial killer, known as the "Brain Surgeon," is terrorizing Miami. This killer is particularly brutal, and Dexter becomes obsessed with tracking him down. The investigation leads Dexter to discover that the Brain Surgeon is a former patient of Dr. Evelyn Vogel, a neuropsychiatrist who specializes in psychopathy. Vogel becomes a significant character, as she has a deep understanding of Dexter's psyche and his "Dark Passenger."

Vogel reveals to Dexter that she was involved in his upbringing, having worked with Harry Morgan, Dexter's adoptive father, to help him manage his urges. She believes that Dexter is a unique case and wants to help him understand his nature. Dexter is initially skeptical but becomes intrigued by Vogel's insights. He begins to work with her to understand his own identity and the reasons behind his compulsion to kill.

As Dexter and Vogel delve deeper into the investigation of the Brain Surgeon, they discover that he is targeting people who have wronged him in the past. The tension escalates when Vogel becomes a target herself, and Dexter must protect her while also trying to stop the killer. The relationship between Dexter and Vogel becomes increasingly complex, as she pushes him to confront his past and the morality of his actions.

Debra, meanwhile, is struggling with her own demons. She becomes increasingly disillusioned with the law and her role in the police force. Her mental state deteriorates, leading her to make reckless decisions. She becomes involved with a new character, Elway, who is a private investigator. Their relationship is tumultuous, and Debra's emotional instability causes friction between them.

As the season nears its climax, Dexter finally confronts the Brain Surgeon, who is revealed to be a man named Oliver Saxon. The confrontation is intense, with Dexter using his skills to outsmart Saxon. However, Saxon manages to escape, leading to a tense cat-and-mouse game between the two. Dexter's determination to stop Saxon intensifies, fueled by his desire to protect those he cares about, including Vogel and Debra.

In a shocking turn of events, Debra discovers that Dexter has been keeping secrets from her, including his relationship with Hannah and his true nature as a killer. This revelation leads to a confrontation between the siblings, where Debra feels betrayed and struggles to reconcile her love for Dexter with her horror at his actions. The emotional fallout from this confrontation is significant, leading Debra to make drastic choices about her life and her relationship with Dexter.

The season culminates in a dramatic showdown between Dexter and Saxon. Dexter finally captures Saxon, but in a moment of vulnerability, he hesitates to kill him. This hesitation allows Saxon to gain the upper hand, resulting in a violent struggle. In the chaos, Debra intervenes, but she is critically injured in the process. Dexter is devastated by her injury, feeling responsible for putting her in harm's way.

In the aftermath, Dexter is faced with an impossible choice. He must decide whether to save Debra or to kill Saxon. Ultimately, he chooses to save Debra, but the emotional toll is immense. Debra dies in his arms, leaving Dexter shattered and alone. The season ends with Dexter grappling with the loss of his sister and the realization that his life will never be the same. He decides to go on the run, leaving behind his old life and the people he loves, as he seeks to escape the consequences of his actions and the pain of his loss.

In the ending of "Dexter" Season 8, Dexter Morgan fakes his own death and escapes to Argentina, leaving behind his son Harrison and his sister Debra, who is in a critical state after being shot. Debra dies in the hospital, and Dexter, heartbroken, decides to leave his old life behind.

As the final episodes unfold, the tension escalates. Dexter Morgan, having been cornered by the consequences of his actions, finds himself grappling with the loss of his sister, Debra. In the penultimate episode, titled "Remember the Monsters?", Dexter is faced with the reality of his life choices. Debra, who has been shot by Oliver Saxon, is in a hospital bed, struggling for her life. Dexter is devastated, and the emotional weight of their bond is palpable as he sits by her side, reminiscing about their childhood and the bond they shared.

In a heart-wrenching moment, Debra's condition worsens, and she ultimately succumbs to her injuries. Dexter is left shattered, holding her hand as she takes her last breath. This moment marks a significant turning point for Dexter, as he realizes the impact of his dark life on those he loves. The loss of Debra serves as a catalyst for his final decisions.

Following Debra's death, Dexter is pursued by the law and the consequences of his vigilante justice. He confronts the reality that he cannot continue living as he has. In a desperate bid for freedom, he stages his own death. He meticulously plans the scene, making it appear as though he has perished in a hurricane. He leaves behind a note for his son, Harrison, expressing his love and the hope that he will have a better life without him.

In the final moments of the series, Dexter boards a boat and drives it into the stormy waters, allowing the world to believe he has died. However, he ultimately survives and makes his way to Argentina, where he hopes to start anew. The series closes with Dexter alone, reflecting on his life choices, as he leaves behind the chaos and pain of his past.

As for the fates of the main characters: - Dexter Morgan escapes to Argentina, leaving behind his old life and the people he loves. - Debra Morgan dies in the hospital after being shot, marking a tragic end to her struggles. - Harrison, Dexter's son, is left in the care of others, unaware of his father's true fate. - Other characters, such as Hannah McKay, are left with unresolved futures, as Dexter's departure leaves a void in their lives.

The series concludes with Dexter's isolation, emphasizing the consequences of his actions and the toll they have taken on his relationships.

In the final episode of "Dexter" Season 8, titled "Remember the Monsters?", there is no post-credit scene. The episode concludes with Dexter Morgan making a significant decision regarding his life and the people around him. After a series of intense events, including confrontations with his sister Debra and the fallout from his actions throughout the season, Dexter ultimately chooses to leave Miami behind.

The last moments of the episode show Dexter on a boat, contemplating his life and the choices he has made. He drives the boat into a storm, symbolizing his desire to escape his past and the chaos that has surrounded him. The screen fades to black, and the series ends without any additional scenes or post-credit content.

In Season 8, Debra Morgan struggles with the aftermath of killing LaGuerta and her feelings of guilt and trauma. She becomes increasingly unstable and begins to spiral out of control, leading to a significant rift between her and Dexter.

Dexter Morgan becomes obsessed with tracking down the Brain Surgeon, a new serial killer who is targeting victims in Miami. He uses his skills to investigate the murders and ultimately confronts the killer, leading to a tense and dramatic showdown.

In Season 8, Dexter rekindles his relationship with Hannah McKay, a former love interest and fellow killer. Their relationship becomes complicated as Dexter tries to balance his feelings for her with his responsibilities as a father and his dark urges.

Dr. Evelyn Vogel is introduced as a neuropsychiatrist who has a deep understanding of Dexter's psyche. She helps him navigate his feelings and the challenges he faces, while also revealing her own connections to his past and the origins of his dark urges.

In Season 8, Detective Joey Quinn becomes more involved in the investigation of the Brain Surgeon and struggles with his feelings for Debra. His character faces challenges as he tries to support Debra while dealing with his own professional and personal dilemmas.

"Dexter" Season 8 contains several scenes and themes that may not be suitable for children or sensitive viewers. Here are some potentially objectionable aspects:

1. Graphic Violence: The show features explicit depictions of murder and bloodshed, including scenes of Dexter Morgan engaging in his vigilante killings.

2. Mature Themes: The series explores complex themes such as morality, justice, and the psychological effects of trauma, which may be difficult for younger audiences to understand.

3. Sexual Content: There are scenes that include sexual situations and suggestive content, which may not be appropriate for younger viewers.

4. Strong Language: The dialogue includes frequent use of profanity and strong language throughout the series.

5. Psychological Tension: The show often delves into dark psychological themes, including the mind of a serial killer, which may be unsettling for some viewers.

6. Death and Grief: Characters experience significant loss and trauma, leading to emotional and intense scenes that may be distressing.

These elements contribute to the overall mature rating of the series, making it more suitable for adult audiences.