Six months have passed since Debra shot LaGuerta. She exchanged her career at Miami Metro for a PI job at a private security firm and has gone undercover for a case.
Meanwhile, Miami Metro is investigating the murder of a man who is missing a certain piece of his brain. The team gets assisted by Dr. Evelyn Vogel, who seems to have a particular interest in Dexter.
Songs: (Unknown artist) -- What A Wonderful World (instrumental)
Dr. Vogel shows Dexter an old video that explains how she knows everything about him and Harry's code. She tries to convince Dexter that the Brain Surgeon must be one of her former patients and she wants Dexter's help to end his killing spree, the Dexter way.
Meanwhile, Debra has resurfaced and stops by at Miami Metro to talk with Quinn about his pending investigation of the motel murder.
Dexter continues his manhunt for the Brain Surgeon. Dr. Vogel tries to prove to Dexter that he’s perfect as a psychopath. Debra’s PTSD kicks in and she makes a desperate plea to confess to LaGuerta’s murder.
Dexter tracks down another potential serial killer from Dr. Vogel’s list. Quinn celebrates his passing of the Sergeant’s exam by defending Debra’s honor in a fight. Dr. Vogel begins treating Debra for her PTSD.
Dr. Vogel comes into contact with the Brain Surgeon, and Dexter and Debra try to keep her safe. Meanwhile, Masuka learns that he has a daughter.
Dexter has a possible candidate for his work, a youthful psychopath. At the same time, Debra and he get back to basics before an unexpected interruption.
Dexter tracks down Hannah to see why she is back in Miami. He also takes on a protégé and begins teaching him the Code.
Dexter suspects that his protégé murdered an innocent person. Meanwhile, Dexter tries to help Hannah flee the country.
Dexter investigates a murder. Meanwhile, Vogel gets the surprise of her life when someone from her past returns.
Dexter enlists Dr. Vogel's help to lure the Brain Surgeon to a location in order to get him on the table. Later, an important person in Dexter's life is murdered before his eyes.
Dexter is torn between fleeing the country with Hannah and Harrison, and taking Saxon out once and for all.
Season 8 and the series conclude with Dexter facing impossible odds. With a hurricane threatening Miami, Dexter becomes determined to end things his way.