Episode four begins with Dexter's struggle with his lack of faith. He sees that there is a power of renewal with brings peace to those who believe. Though he sides on science he can't deny that science has done nothing to make faith obsolete. Sam, The Good Shepherd Auto Repair guy, raises the fact that Dexter, though choosing science, does believe in something greater than himself. Dexter has a seed of doubt about his empty view of things as the beginning sequence closes.
The story shifts immediately to the crime shown at the end of the previous episode: an elaborate recreation of the four horsemen of the apocalypse melded to another victim which has been dismembered and displayed on the mannequin riders posed on the four horses. The killer wants credit as he displays his omega emblem prominently on the forehead of one of the horses. Dexter comes to the conclusion that the "Doomsday Killer" is a man of faith, though he's a "horse of a different color", meaning his skewed interpretation of his religious beliefs must be imposed upon mankind who falters by the choice of freewill. Soon, Dexter discovers the killer is sending messages through numbers hidden in the victims on small pieces of paper. There seems to be, perhaps, a loose connection to clues Dexter's brother, the "Ice Truck Killer" used…But, it is more enigmatic. Soon a department meeting raises Deb's new replacement's stock as he connects the killer to acting out the book of Revelation. Dexter surmises the numbers separate days of the killings and they are a countdown. Dexter starts reading Revelation and it makes him question that with the graphic horror depicted why anyone would find comfort in a faith of which this is a part of. Sam and Dexter interact once more and Dexter finds it interesting that Sam brings up human nature is a driving force in how each person's faith, and their actions, differ. Dexter realizes he is going to have to really delve deeper to understand this killer and he notices there are differences which indicate two different people are involved. Dexter believes the killer has an assistant who must be working under his influence. As this act closes Dexter's son may be feeling ill from a "bug" or something?
Masuka realizes his new hire is a huge mistake. Debra dresses as a professional, but her first news conference is anything but as she goes into the mode of being "Deb" while fielding reporter's questions. Battista and Quinn get wasted while working in the field. Things are spinning out of control and Dexter is gripped with fear of his son's welfare. Harrison suffers from an alarmingly high fever and is rushed to the emergency room due to a ruptured appendix. Sam comes to the hospital offering Dexter "backup" in his time of need. Dexter comes back to his thoughts of things larger than himself as Sam tells him we have to surrender things we can't control. Their conversation turns to Sam relating to Dexter how his earthly father misled and used him for evil, meaning he misplaced his belief which eventually led to prison. In prison, while Sam was attempting to kill a man he despised, he had a revelation to let the old Sam, who had believed in the wrong person go. He literally saw the light and he began his path to redemption leading to the man he now is. Dexter is, of course, conflicted, but he sees there is a need to relinquish things he cannot control. Dexter asks God for help by praying he is willing to submit himself in this time of need. Soon the doctor tells Dexter Harrison came through well and we see Dexter struggles with what he has prayed and what he has a hard time still accepting. Dexter's father comes to him in Harrison's hospital room and tells Dexter he has to admit his prayer was answered. Furthermore he submitted himself in his prayer. Dexter, being obstinate, says he was desperate to which his father warns him he should be ready to follow through on his word. Things are settling back down to a more "controlled" status, but is Dexter still in control? There's a shift starting to occur within Dexter and there are many things, the viewer senses, which as a result will soon unfold.
Battista and Quinn return from their "excellent adventure" with a big break as they now have key evidence who the "Doomsday Killer" is likely to be. Masuka proves his worth as he realizes something strange in that the second murder involved an ancient artifact such as a sword. Even Deb escapes the wrath of her boss as her openness has been embraced by the public at large. Everyone seems to have come out of the swirling chaos, but is it only temporary? The "Doomsday Killer" strikes a third time, officially becoming a "serial killer", insuring everyone's reprieve to be temporary. The highly symbolic, and very elaborately staged, third murder actually made the department complicit as an unwitting officer tripped a wire causing the victim's death to occur in front of everyone's eyes. In one moment everything is changed and the department seems helplessness and inept.
Wow, things really are ramping up, and fast. The season is getting better by the episode. We are mandated to stay tuned…In a word, excellent.