!!SPOILER ALERT!! Do not read if you haven’t watched yet.
The series finale of Dexter centers on the relationship between Dexter and his sister Deborah. It picks up right where last week’s episode left off. Dexter and Harrison are on their way to meet Hannah at the airport. While waiting at the gate, Hannah calls Dexter from the bathroom and tells him that Elway is also there waiting for them. Dexter has to think fast, and comes up with a pretty ingenious plan. He picks up a backpack along with a few suspicious items from the gift stand, drops it in a very conspicuous spot, and then tells the woman at the gate that he saw Elway drop the bag and walk away. Airport security swiftly apprehends Elway, and the problem is solved… well almost. Due to a possible security concern, the gate is evacuated to deal with the abandoned bag leaving Dexter, Hannah, and Harrison unable to make their flight.
Angel, Quinn, and Masuka are all in attendance as the paramedics prepare to transport Deb to the hospital. Angel wants to call Dexter and tell him about the shooting. However, Deb protests saying that Dexter is leaving with Harrison, and if they call him, he won’t go. Quinn insists on riding along in the ambulance.
Deb tells Quinn that when she got shot, she thought she was going to die, and that she was getting what she deserved. Quinn disagrees. He tells Deb that she’s a good person, and that she does a lot more good than bad, and that’s what counts. In the hospital, as they take Deb away to surgery she tells Quinn she loves him. Mathews tells Angel that Dexter has to know what’s going on and decides to make the call himself.
On his way to the car, Dexter gets a phone call from Mathews. He informs Dexter that Deb was shot by Vogel as he made his escape. Dexter heads to the hospital to see Deb. Meanwhile, Vogel hijacks a guy’s car. Most of Miami Metro meets Dexter at the hospital to show their support. Elway, frustrated he can’t contact the Marshal decides to call the field office and finds out about Clayton’s death. He then decides to take matters into his own hands.
Back at the hospital, Deb is out of surgery and surprised to see her brother. Dexter feels guilty. He apologizes for leaving Vogel alive. Deb explains that Marshall Clayton messed everything up by freeing Vogel. Dexter persists and says that he screwed up her life. Deb tells him it’s not his to screw up and that she’s responsible for her own choices. All she wants is for her brother to be happy. The doctor comes in and sounds optimistic. Deb tells Dexter she’ll be fine and although Dexter wants to stay, she says, “The next word I want to hear from you is goodbye.” Dexter abides and Deb says she’ll see him soon. Unbeknownst to Dexter, this is the last time he’ll ever talk with his sister.
Before leaving, Dexter tells Harrison this is where he was born. We then experience a flashback to the first time Dexter saw Harrison with Deb in the maternity wing. Dexter tells Deb that he and Rita picked the name Harrison, and Deb thinks their dad would have loved that. It’s very touching to see the siblings enjoying life in a simpler time.
When Dexter attempts to leave the hospital, he is confronted by Elway who tells him that he knows all about Dexter’s plans to flee the country with Hannah and accuses him of being responsible for Clayton’s death. Dexter pushes Elway against a wall and threatens him to stay away. As Dexter turns to walk away, Elway warns, “A storm’s coming buddy, and it’s gonna be real hard to find a way out.”
Vogel, still bleeding from the gunshot wound inflicted by Deborah, threatens a veterinarian to stitch his wound. Meanwhile, Dexter meets up with Hannah again. They plan on taking a bus out of town. Back at the vet’s office, Vogel, freshly stitched sees a news report about how Deb is recovering at the hospital. He tells the vet to grab his keys. He’ll be taking him as a hostage.
At the bus stop, Dexter decides last minute that he can’t leave with Deb in the hospital and Vogel still on the loose. He leaves Harrison with Hannah and tells them that he’ll see them in Argentina as soon as he can. Harrison tells Dexter that he loves Hannah, and Dexter tells his son that he does too.
Vogel and the vet arrive outside the hospital. The vet swears he won’t say a word to anyone, and Vogel replies, “I know” as he pulls out a scalpel. He cuts the man’s tongue out and then forces him into the hospital. With all eyes on the victim, Vogel slips by undetected and looks for Deborah.
At this point, Dexter returns to the hospital, and seeing all the activity by the entrance, deduces this was likely a distraction caused by Vogel. He rushes up to Deb’s floor and finds Vogel. Dexter grabs a fork, and Vogel readies his gun. Just as the two are about to confront each other, we hear Angel say “Drop it!” Angel, gun drawn, walks up and apprehends Vogel. Dexter then rushes to Deb’s room, but she’s gone. He finds a tearful Quinn who fills Dexter in on what happened. Deb was rushed to the I.C.U. with complications. According to her doctor, a blood clot formed during surgery which caused a major stroke. Deb’s brain was deprived of oxygen for a period of time. Based on her brain scans, she will no longer be able to think, reason, or even know he’s there.
Quinn is optimistic thinking Deb will pull through and says he hears about miracles all the time. Her doctor says recovery WOULD be a miracle and Dexter responds by saying he’s never seen a miracle. [Flashback] Dexter holds Harrison for the first time. Deb tells Dexter that he has always taken care of her ever since they were kids. He used to stay in her room and protect her from the “monsters” which were actually just shadows. Deb tells her brother, “I know you’re gonna be a great father, because you’ve always been a great big brother.” Back in the present, Dexter thinks to himself, “You were so wrong Deb.”
Hannah tells Harrison all about Argentina as he falls asleep on his arm. Suddenly, Elway grabs her arm from the next row. He tells her that when they arrive at Daytona, he’s going to turn Hannah in to the US Marshal Office, and give Harrison to child protective services.
Back at Miami Metro, Angel and a distraught Quinn interrogate Vogel. Quinn screams at Vogel who pretends not to know who Deborah is; Dexter watches on from outside. On the bus, Hannah offers Elway some tea. While he accuses her of poisoning the tea, she grabs a syringe and injects him with a horse tranquilizer. The bus stops and Hannah leaves with Harrison.
Under the guise of running a GSR test, Dexter visits Vogel in his holding cell. He looks around at the security cameras as he enters. He says he wishes he could blame Vogel for what happened to Deb, but he knows it’s his own fault. Dexter tells Vogel that he has opened his eyes and taken away this foolish dream of having a happy life. He then explains to Vogel that he is going to kill him with the pen which sits between them on the table. Just as he expects, Vogel picks up the pen and stabs him in the shoulder. Dexter pulls the pen from his shoulder and stabs Vogel in the carotid artery, finally killing “the brain surgeon” and avenging the deaths of his creator/mother figure Dr. Vogel, his apprentice Zach, his neighbor Cassie, and for the shooting of his sister, Deborah.
Now Dexter has some explaining to do. He has to explain to Angel and Quinn why he was in the cell with Vogel and why he wound up killing him. Dexter explains he wanted to look the man who shot his sister in the eye and administer the test himself to make sure it was done correctly. He explains that Vogel attacked him and he stabbed the killer in self-defense. They are surprisingly understanding; finally giving Dexter the vindication he always wanted for his work. Quinn even goes so far as to say he wishes he could have killed Vogel himself.
Dexter returns to the hospital this time on his boat via the hospital’s dock. The hospital is evacuating due to the impending storm and in all the commotion, Dexter returns to Deb’s room. He says to Deb, “I won’t leave you like this. I’m your big brother.” He flips the switch shutting off Deb’s life support while whispering into her ear, “I love you Deb.” Deborah dies and Dexter wheels her outside on a gurney. He then picks her lifeless body up and walks back onto his boat.
Dexter heads toward the storm, but stops a few hundred yards away with thunder and lightning all around him. He calls Hannah and talks to his son one last time. He tells him he loves him, and he’ll see him soon. Dexter tosses his phone, and then walks over to Deb. Ironically, the last body Dexter drops into the ocean is that of his own sister. In Dexter’s final monologue, he explains that as long as he is alive, the ones he loves will never be safe. Dexter then drives head first into the storm.
In the epilogue of the episode, the remains of Dexter’s boat, the Slice of Life, are found and he is presumed dead. We see his friends and loved ones react to the news of his death. In the end, we are left with one final scene. A lumber worker returns home from a hard day’s work. It is revealed to be Dexter. Believing this is the best way to protect Hannah and Harrison from himself, he lives in isolation.