12 Episodes · Premiered September 27, 2009 · Ended December 13, 2009
Dexter as a father and husband struggles to figure out how to survive for years to come. He seeks to learn from Arthur Mitchell, a serial killer and family man, who has murdered for over thirty years without being discovered.
Dexter's sleep deprivation puts both his day job and his nighttime hunting in jeopardy. Lundy is back in town to capture the Trinity Killer - someone he can't even prove exists.
A sleep-deprived Dexter desperately tries to remember where he hid the body parts of his latest victim.
When a local vandal begins stirring up trouble, Dexter's neighborhood becomes vigilant and wary, two things Dexter doesn't need.
While Rita and the kids are out of town for a wedding, a police officer comes onto Dexter's radar.
Recent events spur Dexter into his own investigation of the Trinity Killer.
Dexter knows it's only a matter of time before police discover the Trinity Killer's latest act.
With family and work taking its toll, Dexter accidentally makes a serious mistake. Meanwhile, Quinn starts digging into Dexter's past.
Dexter has always known his father's code was meant to protect him from exposure; but after committing a serious mistake, he wonders if it could have been designed to protect him from something even more dangerous - human emotion.
Dexter uses Thanksgiving as an opportunity to get closer to his most dangerous adversary yet.
Dexter makes a startling discovery while stalking the Trinity Killer.
Dexter's worst fears are finally realized. Meanwhile, Debra is on the verge of uncovering the identity of the Trinity Killer.
Dexter is obsessed with getting the Trinity Killer himself, especially after Arthur has tracked him to Metro Homicide and learns his real identity.
