Dexter is intrigued by a serial killer who seems to have mastered the bloodless dismemberment of his victims and who invites Dexter to try to catch him. Meanwhile, as his relationship with Rita unexpectedly heats up, Dexter tries to dodge the increasingly familiar advances of his lieutenant.
A cop is murdered and a mob boss orders a hit on the cop's wife. Debra gets her transfer from vice to homicide.
Debra enlists Dexter help in finding the "Ice Truck Killer" who recently resurfaced. Rita gets a visit from someone who her incarcerated husband owes money.
The Ice Truck Killer makes the case more personal by leaving photos from Dexters childhood at the crime scenes. He also arranges body parts to give Dexter clues about his past.
One of the ice truck victims turns up alive giving Debra hope of finding the killer. Meanwhile, Dexter stalks a tracks down the murderer of Rita's friend's fiance, which turns out to be more complicated than he anticipated.
The Ice truck Killer is on to Dexter and leaves evidence that puts Dexter under the scrutiny of the Homicide Department.
When the Ice Truck Killer's identity is revealed, Dexter suspects that something is not right.
A high profile woman turns up dead and it appears to be suicide. Her death reveals a pattern of murders, sending Dexter to stalk a killer unlike any he's encountered before.
Dexter takes a weekend vacation when he learns that his biological father has died and left him a house and all his belongings. Rita comes along for the weekend and then later Debra and Rudy join them. Meanwhile, Doakes has to deal with IA investigating him for a questionable shooting.
The Ice Truck Killer leaves Dexter a horrifying crime scene which forces him to confront problems from his past.
The Ice Truck Killer leaves a crime scene at Santa's Cottage, but the killer has left some evidence Dexter can use. Then Debra is kidnapped to lure Dexter into a trap. And back at the station, Sgt. Doakes begins to suspect that Dexter might be the Ice Truck Killer.
Dexter follows the clues that the Ice Truck Killer left for him trying to find Debra and the Ice Truck Killer. Doakes still thinks that Dexter could be the Ice Truck Killer and tries to stop Dexter on his hunt for the Ice Truck Killer. Paul tries to convince Rita that she shouldn't have her children around Dexter.