Season synopsis
Contains spoilers for this season and earlier seasons.
Six months after Debra shoots LaGuerta, she has left Miami Metro and is working private investigations while misusing drugs and blaming herself for what happened. Dexter finds her spiraling and tries to bring her back into his life. At the same time, Miami Metro investigates the Brain Surgeon, a killer who removes pieces of victims’ brains. Dr. Evelyn Vogel, a psychiatrist who helped Harry shape Dexter’s code, arrives with knowledge of Dexter’s childhood and asks him to find the killer. Debra and Dexter eventually reconnect, while Dexter takes Zach Hamilton, a young murderer, under his guidance.
Vogel’s link to the Brain Surgeon becomes personal: the killer is her son, Daniel, living under the name Oliver Saxon after faking his death. Dexter’s renewed relationship with Hannah McKay gives him a chance to leave Miami with her and Harrison, and Debra returns to the police and resumes her relationship with Quinn. Vogel tries to reach Saxon, but he kills her. Dexter captures Saxon and, choosing to let the police handle him, calls Debra to make the arrest. U.S. Marshal Max Clayton follows her; Saxon kills Clayton and shoots Debra before escaping.
Debra survives surgery, but a blood clot causes a massive stroke and leaves her in a persistent vegetative state. Dexter visits Saxon in police custody and kills him with a pen after Saxon attacks him; Batista and Quinn accept the self-defense account. As a hurricane approaches, Dexter returns to the hospital, tells Debra he loves her and turns off her life support. He takes her body to sea and drops it into the water, then steers his boat into the storm. Hannah and Harrison reach Argentina and learn Dexter is presumed dead, but the final scene reveals him alive under another identity, working at a lumber company in Oregon.