Dexter and Arthur find themselves on a collision course, as Debra unearths a shocking long-hidden truth, Rita admits her marriage to Dexter is troubled, and Batista and LaGuerta face the consequences of an ethics breach.

Dexter figures out who the Ice Truck Killer is, along with a dark secret from his troubled past. Meanwhile, La Guerta is replaced with a new boss and Angel figures out a way how to track the killer while he's still in hospital.

Dexter must buy time to protect himself when Debra's investigation brings the department one step away from identifying Arthur as the Trinity Killer; Rita confides in Dexter, but is disappointed in the result.

Dexter realizes it won't be easy to end things completely with Lila. Dexter tries to stay ahead of the investigations as the manhunt for the Bay Harbor Butcher intensifies. An enemy of Dexter figures out his secret.

For most people, Thanksgiving is a time for traditions and family. But for Dexter, it’s an opportunity to get closer to his most dangerous adversary yet. As Dexter gains insight into Arthur’s psychology by studying those closest to him, he finds himself drawn into a bizarre and twisted world.

After witnessing her brother kill, Debra attempts to reconcile with Dexter while struggling to cover up their involvement with the murder.

The Ice Truck Killer sets a trap for Dexter by kidnapping someone close to him; Dexter's increasingly odd behavior piques Doakes's interest.

Dexter must protect himself when LaGuerta closes in on his secret.

Special Agent Lundy and the FBI finally settle the case of the Bay Harbor Butcher, but the heat's not entirely off Dexter as the flames literally close in.

Dexter gets some much-needed R&R time with Rita and the kids out of town, leading to his stalking of a new victim until he unexpectedly begins to empathize with his target, a cop that murdered her family.

Dexter finally believes he understands the beast known as Trinity. But when a ten-year old boy goes missing, Dexter is forced to question everything he’s learned up to this point.

The Ice Truck Killer prepares a crime scene for Dexter: a hotel room all covered in his previous victim's blood. But Dexter does not appreciate this gift, because his childhood memories hunt him.

Dexter and Homicide race against a lunar eclipse to catch the Doomsday Killers before their final gruesome act; Debra struggles with a new emotional reality.

Dexter is attacked by the man who murdered his mother. Meanwhile, Lila wants to get closer to Dex, and Debra and Lundy close in on the Bay Harbor Butcher.

Dexter must make a massive decision that will have an effect on all those he holds close. Lila meanwhile is back with a secret to blackmail Dexter.

A series of chess-like moves ensues when Dexter and Miguel vie for the upper hand, with Miguel winning Rita's affection by presenting her with a lavish wedding gift. Elsewhere, Debra wonders if her relationship with Anton is worth the trouble.

The Ice Truck Killer leaves a clue at the scene where Dexter has dispatched his latest victim, and Dexter is worried that someone might have witnessed his killing. Rita is trying to deal with her ex-husband.

Dexter appears to be connected to a psychiatrist suspected of murdering a suicidal patient.

Doakes follows Dexter to his next crime scene and shocks him with a revelation about Harry. The Bay Harbor Butcher task force feels they are zeroing in on their man.

Dexter is inspired to investigate the Trinity Killer on his own, while Debra blames herself for an event that was out of her control, and Rita realizes how little she knows her husband after discovering one of his secrets.

Dexter and Lumen hunt for their next victim; Debra uncovers new evidence in the Barrel Girl case

Homicide uncovers some key evidence linked to one of Dexter's and Lumen's prior victims; Debra identifies two more suspects in the case.

As Christmas approaches, Dexter tries to balance his life with Hannah and his relationship with Debra. Dexter learns the man responsible for ordering his mother's death has been released from jail.

While preparing for his big wedding day, Dexter has to figure out a way to remove Miguel from his life for good. In the meantime, Rita has troubles of her own, when Syl reveals that Miguel has been seeing one of his old flames. Debra finds a new clue that brings her even closer to catching the Skinner.

It is the day before Dexter's wedding and Dexter must deal with two people targeting him, while preparing for his special occasion. Meanwhile, Angel tells Deb he's put her in for a promotion, but after he finds out some information her shield may be gone before she gets it.