Dexter and Arthur are on a collision course.

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.

Dexter learns more about Arthur's bizarre and twisted world, while Rita has her hands full preparing Thanksgiving dinner for a full house, Debra uses the holiday to further investigate Trinity, and Batista gets closure on an old case.

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.

Rita goes to a wedding with the kids, allowing Dexter to have his own little vacation. He does what he does best when alone, hunt, and goes after an officer with a dark secret.

The disappearance of a ten-year-old boy forces Dexter to question his assumptions about Trinity, while Cody defends one of Dexter's lies and Masuka is unable to face what he witnessed on Thanksgiving.

Dexter Morgan is sent to investigate a blood-soaked crime scene, and is gripped by a suppressed memory. Meanwhile, Rita is charged with assaulting Paul and could lose the children in a custody battle. Angel investigates a hunch regarding The Ice Truck Killer.

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; Debra wonders if her relationship with Anton is worth the trouble.

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.

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.

The strange suicide of a powerful woman leads Dexter to suspect her shrink of murder, but he gets a shock when a visit to the suspect opens up dark secrets from Dexter's past.

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 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.

Dexter must find a way to get rid of Miguel despite the fact that his friend is a highly placed district attorney and also Dexter's best man, and Debra finds a new clue to the Skinner's identity.

Dexter attempts to calm the unstable Ramon now that Miguel is out of the picture; Debra is about to receive her detective's shield but is blind-sided with information that could derail her promotion.