The fifth season of Dexter premiered on September 26, 2010, and consisted of 12 episodes. The season focuses on how Dexter comes to terms with the aftermath of the Season 4 finale, stopping a group of serial rapists and avoiding a corrupt cop who learns his deadly secret.
Dexter must make a choice; Quinn stirs up trouble for Dexter but supports Deb.
Dexter tries to focus on the children and fight his dark urges; Debra ends up on Quinn's doorstep.
Dexter hires a nanny; Debra is annoyed with her new partner; Quinn continues to investigate Rita's murder.
Dexter must save a life; Deb has a confrontation with a key suspect; Quinn follows up on the similarities between Dexter and Kyle Butler.
Dexter is saddled with an unwanted conspirator; Dexter worries about how Rita's death will affect Harrison; Deb works alone; Quinn enlists an old friend's help.
Dexter is drawn into a precarious situation; Batista discovers an interesting lead; Quinn gets information about Dexter from a questionable source.
Dexter is called to investigate a horrifying crime scene; the Santa Muerte case leads to a violent standoff between Debra and the Santa Muerte killers.
Dexter and Lumen vet and stalk a violent killer; Debra gets into some unexpected trouble from the fallout of the Santa Muerte case
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.
Dexter must do damage control; Debra's speculation begins to take shape; Quinn becomes involved in a homicide.
Dexter's situation grows desperate when he discovers that Lumen's been set up. Despite knowing he's being baited into a trap, Dexter risks everything to make sure he doesn't fall into the same mistake again. In the Barrel Girls case, Debra lets her personal feelings lead her instincts once she concludes that vigilantes are more than just a theory. Quinn finds himself in a troublesome situation, which only Dexter can help him out of.