Six months after the season finale, Dexter is now living with three kids and a wife in a new home.
Along with his new son Harrison, the complexities of being a suburban father of three is making it difficult for Dexter to concentrate on his work.
His lack of sleep leads him to let a murderer walk by bringing the wrong documents to court and puts a strain on his life outside of the office.
Also, a now retired Agent Lundy has returned to finally capture the "Trinity Killer" who has arrived in Miami.
John Lithgow plays Arthur Mitchell, an unassuming, mild-mannered suburbanite who has been living a duel life as one of America's most prolific and deadliest serial killers.
Dubbed the Trinity Killer because of his proclivity to kill in threes, he relocates to Miami after being tracked by Special Agent Frank Lundy (Keith Carradine).
Brought on to assist in the investigation of Miami's latest serial killer, Dexter becomes fascinated with Trinity's unique killing methods and his ability to evade capture for almost three decades.
Produced by Showtime, Dexter is executive produced by John Goldwyn, Sara Colleton, Scott Buck, Manny Coto, Tim Schlattmann, Wendy West, Jace Richdale and Michael C. Hall.