Ep 15. Repo Man

In Supernatural season 7 episode 15, titled "Repo Man", the Winchesters are called to investigate a bizarre series of murders occurring in a small town. Upon arriving, they discover that the killer is the infamous "Demon of the Week" known as Jeffrey, who had possessed a man named Les six years prior and had been living inside him ever since.

As Sam and Dean investigate, they learn that Les had made a deal with Crowley in order to become a successful banker, but had failed to uphold his end of the bargain. As a result, Crowley had sent Jeffrey to possess Les and exact revenge.

Meanwhile, Sam begins to experience hallucinations and flashbacks to his time in the cage with Lucifer. As he tries to keep his sanity, he discovers that Jeffrey had possessed him as well during that time and had been manipulating him ever since.

The episode delves into themes of guilt, redemption, and the consequences of making deals with demons. It also highlights the strained relationship between the Winchesters, as Sam's mental state and secrets threaten to tear them apart.

Overall, "Repo Man" is a tense and emotionally charged episode that explores the darker sides of the show's mythology while deepening the characters' arcs and relationships.