On his road trip, Dexter is accompanied by the "ghost" of his brother, Brian Moser (the Ice Truck Killer), who acts as a chaotic substitute for Harry's guidance and encourages Dexter to abandon his "Code".

Influenced by Brian, Dexter kills a motel clerk who stole his hunting knives. However, by the end of the episode, Dexter rejects Brian’s influence and runs him over with his car, signaling a return to Harry's Code.

Back in Miami, Debra struggles with the pressures of her new Lieutenant role while Masuka and his intern find a lead in the Doomsday Killer (DDK) case.

In the episode (Season 6, Episode 7), Dexter travels to Nebraska after learning that the family of Arthur Mitchell (the Trinity Killer) was murdered, with Arthur supposedly being the culprit. Knowing he already killed Arthur, Dexter suspects Arthur's son, Jonah , is responsible and goes to investigate. Key Plot Points

Dexter discovers that Jonah’s mother had become abusive toward her children, leading to her daughter's suicide. In a fit of rage, Jonah killed his mother. Dexter ultimately chooses to let Jonah live, telling him to forgive himself.