The title of this episode refers, presumably, to the biblical story of the Prodigal Son. This parable relates the tale of a young man who leaves his father's home and then squanders his inheritance. Destitute and alone, he eventually returns home to beg for forgiveness, and his father rejoices and welcomes him back with a great feast. The story represents redemption and God's forgiveness. Contrary to popular usage (and that implied here), the word "prodigal" means overly extravagant or wasteful, particularly with regards to money. Outside of the story of the Prodigal Son, "prodigal" has absolutely nothing to do with leaving, returning, or forgiveness.