In the Season Three premiere, Dexter's life seems to be smoothly back on track, until he targets a dope dealer who's also in the sights of Assistant D.A. Miguel Prado; Internal Affairs pressures Debra to rat on her new partner.
Every cop in Miami is tasked with finding the fugitive Freebo, who is accused of killing the younger brother of Assistant D.A. Miguel Prado; Dexter and Rita move closer to making a big decision about their family.
Dexter encounters a fellow predator - but this one is a pedophile; a murder is pinned on Freebo but Dexter knows the truth; Dexter struggles with the fact of his growing friendship with Miguel.
Dexter scrambles to convince Rita that his marriage proposal is sincere and romantic; Miguel's vengeful brother Ramon searches desperately for their sibling's murderer, who was secretly killed by Dexter.
Dexter hears the story of a husband who has gotten away with murdering two wives for financial gain and tracks the man to Bimini, but Rita has a medical emergency while Dexter has disappeared.
Dexter tests Miguel to determine if his friend has discovered his secret, while Rita loses her job and wonders if she's meant to ever have a successful career.
Dexter begins working with Miguel but they quickly have differences in selecting a potential new victim; Rita discovers that Miguel's wife suspects him of an affair; an old friend of Dexter's asks for help in ending her life.
Dexter undertakes to teach Miguel the Code, but doesn't realize he's whetting his partner's thirst for blood; Debra is one step closer to finding the Skinner, but she can't find Anton.
Dexter and Miguel's friendship becomes strained even as Rita confronts Miguel about his suspected infidelity; Debra searches furiously for Anton when it's revealed that he was abducted by the Skinner.
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 it.
Dexter must find a way to get rid of Miguel despite the fact that his friend is a district attorney (and Dexter's best man); Rita discovers that Miguel has been seeing an old flame; Debra finds a new clue to the Skinner's identity.
In the Season Three finale, 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.