This clip is courtesy of the fourth season finale of Dexter. In it, Arthur barges in on his family.
Showtime says the ending to Dexter's season four finale will shock you. Get excited for it with the episode's official trailer.
In this clip from the season four finale, Deb confronts Dexter with a major piece of information: she knows about his biological mother.

Dexter Season 4 Episode 12 Quotes

Dexter: My dark passenger is ruining my life.
Harry: It is your life.

I want you to disappear from my life like a ghost, a really annoying ghost.