Dexter fights his dark urges, but a shocking discovery puts him on the trail of a new victim; Debra hosts her brother and his children but finds herself squeezed out of her own place.
In an effort to create more free time to stalk and kill victims, Dexter hires a nanny; Debra is annoyed by her new rookie partner; Quinn pursues the theory that Trinity did not kill Rita.
Dexter has to save a life instead of taking one; Deb has a scary confrontation with a key suspect in the Santa Muerte murder cases; Quinn continues following up on the strange similarities between 'Kyle Butler' and Dexter Morgan.
When Dexter is saddled with an unwanted conspirator, he is forced to make some hard decisions about her fate; Dexter wonders if Rita's death has awakened a darkness inside Harrison; Quinn enlists an old friend to look into Dexter.
Trying to get his life back on track, Dexter hunts a new target, but is distracted and drawn into a precarious situation while helping his troubled acquaintance; Batista discovers an interesting lead in the Santa Muerte murder cases.
While helping Lumen, Dexter finds himself on a collision course with Homicide when he is called to investigate a horrifying crime scene; the Santa Muerte case leads to a violent standoff between Debra and the killers.
While attending a self-help seminar, Dexter and Lumen stalk a violent killer; Debra gets into unexpected trouble from the fallout of the Santa Muerte case, forcing Batista to make a difficult decision.
In the midst of hunting their next victim, Dexter and Lumen are surprised by the return of an unannounced guest; Debra is assigned to the file room, but manages to uncover new evidence in the Barrel Girl case.
Dexter discovers a possible ally in the pursuit of Lumen's former captors, but he and Lumen are forced to step down when homicide uncovers evidence linked to one of their prior victims.
In the Season 5 finale, Dexter realizes that he and Lumen are being lured into a trap and risks everything to escape; Quinn needs help that only Dexter can provide.
