Someone close to Dexter manages to track him down. Meanwhile, he questions whether he can suppress the murderous urgings of his Dark Passenger when a local hot shot behaves recklessly.

As Dexter struggles to bond with his son, his cabin becomes home base in the search for Matt Caldwell.

Dexter has to prevent suspicion when the search for Matt escalates to a crime investigation, while Harrison is making a name for himself at school.

The father of the person whom Dexter killed makes a surprising announcement. Meanwhile, Harrison is considered a hero to the entire town after he was involved in a serious incident at school. Angela digs deeper into a missing persons case.

Dexter's method of protecting his son from drugs unleashes his Dark Passenger; Angela and Molly's New York City trip leaves them wondering about a well-respected member of the community.

Someone has discovered Jim Lindsay's secret identity, leading Dexter to realize that he might not be the only serial killer in town. Meanwhile Harrison spirals out of control during a wrestling match.

Dexter turns from predator to protector out of concern that a serial killer has set its sights on someone he cares deeply about. Angela arrests someone who may be the culprit of a cold case. Harrison turns to a very dangerous person.

Dexter and Harrison find themselves closer than ever over Christmas break, bringing father and son into the crosshairs of a serial killer; Angela starts to wonder if Iron Lake is not the safe place she always thought it was.

Dexter and Harrison try to live a normal life in a place that they have discovered is not as normal as they thought it was. Will they live happily ever after, despite all the threats coming their way?